All of your feelings are okay. You can choose your reactions and behavior.

With a critical, alcoholic father, it took years of therapy to get over feeling not good enough.

My joke was I got a master degree to prove to my dead father that I was smart.

Have you tried fossil hunting? Your bio thingy days that you're from Connecticut, and there's lots of Jurassic (200 mya) sedimentary stuff around you. There's also a cool state dinosaur museum listed on the interwebz with lots of preserved dinosaur trackways.
Might give you a more visceral connection with the ancient world, rather than just intellectual.

I’m still fascinated and in awe of the natural world. I get chills thinking about the reality of how unique each one of us is, yet how inescapably connected we are to everything else in the universe! That I can breathe the same air as you, without ever meeting you, or that we share the same material throughout our lives as people who have come before us. It’s astounding.

And I still believe in life after death. But it is a transformed life. My decomposed body will go on living in plants and animals. My life will be remembered by people who have been touched by me or by others who have known me.

Will I be conscious of any of this, probably not. But I think it’s all beautiful to think about. And I am moved by those thoughts.

Give yourself time, and know that you will adjust.
We are all born atheists.
You are just returning to your default position.
If it helps, just think of all that other stuff as fiction, like Harry Potter or Shakespeare, and some folks have decided to live at Hogwart's, or in the household of the Capulets, full-time, like it's really real.

Its a form of cognitive dissonance. Understanding and acceptance arent always companions. just keep learning, and question everything

I feel like it will absolutely take time you know? Imagine going most your life with the name John for example and this is who you are and what you know to one day realize your name was never John, but is Kyle. It would probably take you a long time to accept that your name is Kyle and to get use to it still since you’ve gone so long as John. I guess this is the best way I can put that into perspective. I think its normal to take a while to adjust. I did.

The beliefs you have just shed are more than just "bits of knowledge" to be exchanged for different bits. Things like the age of the Earth, the causes of biodiversity, etc., are things that were instilled in you as a child, and supported by people you trust and love. They are (or were) woven into your sense of identity. Shedding them is not easy, and I'm sure it didn't happen quickly. But that's why the new ideas don't "feel" quite right - they don't have the "roots" that the old ideas had. Yes, it is a matter of time. Don't feel rushed, you're on the right path (evidence, science, reason, etc.)

As odd as this sounds studying different religions broke it for me. NOT studying with them but about them. Looking at world religions and seeing that all they have in common is controlling people, and governments by default, tore religions apart in my mind. And I can't say enough good things about Sam Harris book "Letter To A Christian Nation"

Any change in belief systems require a period of adjustment. The struggle is more profound the more the change has become. For the same reason that Algebra I is considered the most difficult math to grasp. You are introduced to more new concepts that don't necessarily depend on previous knowledge. Learning new knowledge and getting used to new comfort levels will all take time.

It is a matter if time. I have been an active atheist for about 15 years and it was difficult at first. Once you can see through the hold that these religious people have on your thoughts, it is a truly freeing experience. You can live your life on your own terms and make decisions not based on how you will be viewed but what you want to do. I hope that time comes for you soon.

Yes it's a matter of acclimatization. Thought habits take time to break. Also, operant conditioning (in this case, that rational thought is not to be trusted) takes time to reverse.

Find a few science books on geology, especially if you can find one that covers many of the epochs, like those of the dinosaurs, Pangaea, etc., it is all extremely interesting.

Maybe go check out a natural history museum. Seeing evidence instead of just reading about it might help

It doesn’t sound dumb at all. You need to find a counsellor so that you can debrief as you are changing your whole worldview which is both challenging and scary. It’s great to know something in your head but you can’t think your way out of some stuff and until you ‘feel’ it will be as vibrant as knowing 1+1=2. Probably a course of action would be to contact a national counselling body and explain your situation. Good luck

Time and deep learning. You can’t make time go faster, but you do have some control over how much and how fast you learn. The faster you study the sciences (and read books by scientists, like Carl Sagan’s “The Demon-Haunted World” the faster the old worldview fades. Mine lingered for decades, but I don’t feel a trace of it now. I wish I had studied more, earlier.

Congratulations on getting away from the superstition and moving into the world of reason! There's no doubt that portions of our early conditioning hang around forever...sorry to say! But, you'll escape by reminding yourself that it's just a little patch of old brainwashing and YOU won't believe it! Good for you!

There has to be a time of emptying out, putting aside the non-science based things you were taught/believed and the understanding of how matter evolved and where humans fit in.
I think the more you read and sort out the science facts from just a faith belief you will realize the feeling 'right' has more to do with the idea of guilt that is inherent with religious teaching.
Understanding where the feeling originates may help you move beyond it.

I have no idea what you're talking about.
Doesn't feel right? Have YOU been brainwashed!
Forget abut evolution and stick to the 8000 year part: it's OBVIOUS the planet is older than that, since dinosaurs lived at least 65,000 years ago. Did the entire universe appear out of nothing 8000 years ago, or just the Earth?
The wonder is ANYBODY really believes that.
To me it not only feels right, everything about the world around me practically screams it in my ears and makes my eyes hurt from the glare.
The majesty of creation is something awe-inspiring and fills one with wonder. The true mystery of it all takes one's breath away, and is far more powerful than any "religious" experience could ever be, if one just lets it sink in for a moment.
To minimize it is to mock it, because no "god" is capable of simply blinking it into existence.
Try feeling that.

It will become evident when the facts you read about line up with the facts you can verify yourself and the more facts you find. Science works on gathering a large number of facts. The more facts you have, the more solid a hypothesis (prediction) becomes. At one point you will find yourself in a conflict when comparing facts with what you have been told. That will be a cross road. Things will start "feeling right" when you will dispute what you have been told with verifyable facts.

I got my first college degree from a Xian college where I took 5 of the religion classes. Because of that, I also taught a couple of the adult bible study classes at the last church I was a part of. Yes, it was also a "young" earth teaching church, yet, I was one of what I think are many who didn't believe and/or took part of that indoctrination thing allegorically. It took my third time of reading that book to be done with that theistic belief and I finally couldn't deal with the immoral, delusional, nasty, prudish and more behavior of the believers I associated with.

My official agnostic anthem.

It is a matter of reason over training when presented with sound evidence.
The feeling might persist but you override it again and again with logic and empirical evidence

It's just a matter of time; all that childhood socialization fades slowly.

Read about evolution. It's fascinating.

I think it is a matter of exposure to the factual evidence. Understanding how layers of sedimentation form and how that is used to determine the age of fossils found. Actually seeing progressive development of cultural artifacts dug up from strata in the Acropolis, etc. Knowing and being familiar with actual evidence clearly exposed the lies in written material for me pretty quickly.