Also, regardless of age, if you are or have been a student at a music school, they are usually happy to put you in touch with fellow students who want to form a band, although they might not plan to play in public immediately.
I know that my teachers kept telling me to do exactly that - but I only play along records and for my own enjoyment, and so far have no desire to go on stage. (Joining a band is also a fairly big commitment, what with learning the songs in the set, rehearsing, getting all the gear etc. and above all being available when the band need you!)