A lot of the good ones are turning 18 this year, so I assume a lot of them are still in school.
Based off how much of the pre-season they did with NRL though:
Saukuru - Part-time NRL, 19 years old this year.
Faagutu - Part-time NRL, 19 years old this year.
Da Silva - Full-time NRL, 18 years old this year.
Laulilii - Full-time NRL, 18 years old this year.
Miller - Full-time NRL, 18 years old this year.
Feledy - Full-time NRL, 19 years old this year.
Sukkar - Full-time NRL, 19 years old this year.
Lawry - Part-time NRL, 19 years old this year (I think).