Adding onto my post #27, unfortunately casting in HS and youth theatre doesn’t really help kids fine tune their “type” because they play against type all the time. Only in these programs would you have a 14-year old Jean Valjean in “Les Mis,” a 17-year old Papa in “Fiddler,” or a 16 year old Mama Rose in “Gypsy”! 
One suggestion is to look online at videos from college senior showcases, and from programs like the national HS Musical Theatre Awards (not the character songs, but the individual finalist songs) or the Young Arts awards to see what different kids are singing and to get ideas of songs and types – you don’t have to sing the same songs, but you can look up the composers or the shows to find others. Also look for videos of new musical theatre showcases – there are many – to find new works that might feature young-adult characters/types.