BJ are almost 20 years old so the crowd is a very mixed bag of ages. I went to see them on the OWN Tour and there were rockers from about 8 through to about 68 that I could see. As for show length, they usually come on at about 8:00pm (for the UK shows at least) and can play anything from 2 hours 20 mins right through to over 3 hours if the crowd is good and they feel up to it. Hope you enjoy the gig anyway. I'm going to see them in June at Hyde Park and I am so jealous you get to see them this weekend - I have to wait a whole 4 1/2 months.