S.B.
We took my daughter to a Michael McDonald concert when she was 9 and she loved it. It was a smaller, intimate venue and we were very close to the stage. The opening band was really loud and she hated it. We didn't think she would make it through the whole thing, but once Michael started, she was totally into it. It's one of the best concerts I've ever been to. He was amazing. He's a true star so he didn't have the "if you can't be good, at least be loud" thing going on. She's been to lots of concerts, ballets, symphonies, etc. She's an adult now and travels to see her favorite bands.
I personally wouldn't have taken my child that young to a huge coliseum for a concert. Too many people and too much else going on for MY comfort. We lived in Sacramento and lots of great bands played the Arco arena, but we prefer smaller venues.
My friend and her adult daughter went to a concert together in a huge arena and she said they had no idea they asked for the pot smoking section. People weren't even shy about it.
When you get that many people in one place anything can happen.