I would tread carefully there. Who know if it is true or not. Could be or could not be. Good luck there.

If you are pretty sure it's true, it could be the beginning of a new chapter in your life. Take it gently and be prepared to have little in common.

Contact her, what have you got to lose? There is no magic formula that will guarantee anything, just do it . . . . life has no guarantees. My bet is she would be very pleased to find out that there is a real, authentic parent in the world for her.

Carefully and gently

That is a good question. Has she recently been looking for you or information about her biological parents? If not I think I would start with how you learned this. Not sure, but was only thing I could think of.