U 18 (i say under 18 academy with less tokens)

I 'd loved the idea to have an under 18 youth academy which will be producing players of age of 16 and will reguire less tokens to sign. They will appear in a dif. window, lets say academy's (who after all plays at academy field?)Those players will be preparing by training and only participate in friendlies (not in anyone of the three competitions) untill they reach the age of 18 where they can sign to the team for a few more tokens or money. I know that many will say, whats the reason for that?/ The reason is that i see the game as a game and i like it to have as many features as it gets and i am finding interesting that except winning to grow slowly a team.
P.S U21 as we know it could remain the same (sequence, price, etc) and worked in paralell. U18 or to be better rephrased U17 will be an addition.