Is this normal for an 11 year old?

My 11 year old always seemed a little over-developed, he started dating at 11. Him and his girlfriend are kissing, a lot. Ive spoke to several parents and teachers wondering what to do, but they have no answers! He and his girlfriend have been left home alone, I thought 11 year olds had no raging hormones. Do they? I thought boys started getting these uncontrollable hormones at age 13. I'm afraid they have done something while they were home alone. I've caught his girlfriend with her shirt off before! This seems very odd to me. She had a bra on, but I don't want my child to be exposed to this. Do you think he did something? I never gave him condoms, because I thought, why the hell would an 11 year old need condoms! I'm confused and scared quite frankly! We leave them alone for 2 hours per day. But do you really think an 11 year old would even have the courage to ask a girl to have sex? I'm confused! Should I give him condoms? I don't know! So please help me!!