I just came across this post. I have a daughter who is 13. She did a discover scuba session at 11 and just fell in love with it. I couldn't get her out of the water. She got certified right after that.
I feel more comfortable with her in the water than many people I know. We always dive together and we always practice different things when we dive, such as OOA emergencies, air sharing, etc. She is very mature for her age, and very serious too (somethime I think too serious). She "gets" it. I've read a lot of posts here asking if young people know about danger, nitrogen narcosis, etc. She does.
That being said, we use common sense when diving together. Because of the potential effects of excess nitrogen on bones in a growing body, we limit our dives to 40' (yet we still have a great time together). She is very aware of her surroundings and very careful. We always talk about the dive before we do it, what we are going to do, where we are going to and when we are going to turn the dive. She also knows that she can call the dive for any reason, any time...and she has when she just didn't feel comfortable.
She is the definition of grace in the water. She is fortunate that she had good boyancy control right from the start. She can hover at her safety stop without finning or flailing. She is very aware of the environment and takes care anytime we are in the water.
Then I have another daughter. She is now 11. She is starting to express an interest in diving. Will I let her? Not yet. She isn't ready, maturity wise. I told her will wait a year and see how she is diong at that time.
So, would I take my children diving...absolutely...when they are ready and can handle the responsibility.
One other thing I would like to add. We as parents spend a great deal of time overshadowing our children. We hustle them from soccer to dance to swim practice to basketball to football to whatever. But do we every really truly spend time with our children? Diving is my opportunity to spend the kind of time with mu daughter (and hopefully soon my second daughter) that I wanted when I was a child. Its our one-on-one thing. I, for one, love it.
John