I would like to go diving with my 11 year old child, is this possible?

Yes this is possible. Children can start learning to dive from 10 years of age with a PADI Junior program. They can start regular PADI programs from 12 years of age. We do recommend that you buy the book in advance, to read it together with your child and answer the questions. For children the diving as well as the theory might be a little too much.