Originally Posted by 7Ponies
I don't know the extent of your injuries, but the human body HEALS. It also GROWS with you as you grow, even if it has been injured. I would speak with another doctor and ask specifically if you can safely ride, given your past injuries. The only thing I can think of that might "bleed" and "kill" you if you got hit in the stomach, was if you had an aneurysm. (and any person could have one of these, it's not age related).
I broke my back riding, and yes, I could do so again. But for that matter, I could get run over by a truck crossing the street as well.
Don't let fear run your life. Speak with your doctor and find out exactly what you are dealing with now, not what you dealt with when you were 10. The human body is amazing in it's ability to recuperate and continue on :)
I agree with this advise 100%.
You could also find a trainer to do private lessons with; you don't "have" to be involved with a class full of other riders.