The left-back has won the Jimmy Murphy Young Player of the Year trophy.
A signing from Watford, Amass has featured in the Premier League and the Europa League under manager Ruben Amorim.
Amass, 18, has also been captain of England U18s this season.
The defender recently said: "I've been waiting for a long time, being patient so when it finally happened, I got into the dressing room and took it all in for a moment by myself.
"When I first signed, it was about developing as a player, getting better, which I think I've done; it was about enjoying my football, which I think I've done with all the experiences and the trophies, and then it was about getting first-team football. And that's come as well.
"So I think all the reasons I've signed have happened. Next is to keep working hard, to show that people can trust me and that I'm a good person off the pitch as well as a good player. Keep giving my best and hopefully get more minutes."