Need help in choosing who to train

[CSTAR]

Hello,

Hope everyone is doing well and staying safe. I have acquired a few players recently and wanted to get your thoughts on who I should train. I am a lvl 2 manager, with 460 rests. My current top players (in terms of goals/assists) are my AML (31y old) and my AMR (24y old), my ST is bad and would need to be replaced. Now with that context, below are the FTs for consideration:

Thanks in advance!
CSTAR

20y AML: He is World Class FT, but is 20y old, so not sure if I should invest into him or not, my current AML will need replacement end of next season



19y ST: He is Excellent to World Class FT



18y AMR: He is Excellent FT



20y AMR: He is Excellent FT, I didn't realize early on. He was from my starting line up, started as 18y old, but became 19y old with-in
season 1 itself (I joined season 1 when there were 7 days left) and now he is 20y old in season 2