You also need to have similar, or at least complementary, musical goals for the band. If one member wants to do note-perfect covers of Pantera songs, and another wants to vaguely follow Grateful Dead-style jams, you're going to have problems.
I joined at age 15 and heck my drummer is 13 he joined when he was like 12 to 13 i think there is no limit maybe more difficult to do stuff like live music if a venue sells alcohol or renting a studio to record but when it comes to playing and practicing consistently with a group of people there is no age requirement or “must be this tall to ride” type business going on.
