Hello there! So I have a new doubt: Where do you guys think is the best moment to power train a player?

I have 3 young stars that I want to power train a bit:

AMR - 124% - 18 years.
DC - 122% - 18 years.
AML - 124% - 19 years.


They're all fast trainers.

I currently have 240 rest packs. Should I train them now? Since they're younger. Or wait for next season when they drop 20%?