Premature since her first orgasm?

I've been dating the girl for 1.5 years. Last week, she had her first orgasm (from oral and manual) and has been able to do so since then. I'm overjoyed for her, but haven't been able to last more than 5 minutes during sex (which never has gotten her an orgasm even when I used to last 30 minutes) since she began to get off. I think I'm just too turned on. Is this typical? Any suggestions?