"Lastly:
Seventeen is simply the max age a player can still be while on the youth team. At 18, you either promote them, or cut them. If they are cut BUT have a minimal TSP that would actually make them a decently usable player at 18 like say 50 TSP, that cut player goes to the FA market. If they are a terrible player, they just disappear upon being cut.
The initial team of players generated for your team would consist of an even number of four 15yr, four 16yr, and four 17 yr old players for your 12 man roster."
I believe me saying this in my last post actually addresses the issue you brought up before you brought it up. Youths that don't hit a minimum Useful TSP by a certain age And aren't called up to the main team would be removed from the system all together. There's actually something very similar that already happens with low value players that get cut now even so it's really not even a new idea on my part but rather an extension of one already implemented as we speak with normal players.