Are able to take 12 yr olds to concerts?

Contrary to what the other guide has said, you can indeed bring any age children to certain shows. Its on a show-by-show basis, so you works have to check for the particular event you are wanting to attend.

No must be at least 16 with identification

I agree with Michael. It is at the discretion of the performer. I took my 15 year old daughter to a show last month and there were a number of younger kids there with parents.

It depends on the show. Most artists let people know when tickets are sold if it is all ages, 16 and up, or 21 and up.