If im in a band, and im 13, where can we play? We're all between 12-15, and most people recommend starting in pubs, but thats obviously not an option.
School? Ask if you can play at a school show or if you could throw a gig in a suitable space, which schools often have.
School is your best bet - also, any outdoor local events ( festivals, etc.). One thing we did back in high school and junior high was to simply organize a gig at the school - and have it happen there - find another band and make a night out of it.