Hey mumia and welcome to the forum!

Out of curiosity, did you start working on your Youth Academy? Beginning development on your ground resets the timer for youth players. You can find your young players in a few places. Firstly, check your Assistant report on the Home menu - You will have a dropdown that will allow you to sign both, one, or neither of them.

You can also check the Squad screen. They are added to the bottom of the list.