The oldest one in the group, I believe, is 19. 19! And they just released a ridiculous fresh EP on Spotify and iTunes that you need to have in your library immediately (links below). They are each so talented, but more than that they are amazing dudes with a heart for people first and then their music. That simple shift of focus will help carry these guys very far in the music world, and I believe the industry needs more artists with hearts like theirs.
*Also, guys, I better be invited for when you guys get invited to play on Jimmy Fallon.*