First time with a girl was when I was 18. She was one of my best friends and it was incredibly awkward, haha. Fun though, even with all the drama later.
First time with a guy was just before my 21st birthday. It wasn't a pleasant experience, I did not chose him, and I don't even count it as my first (hetero) time, really. The time I count as my first was actually in a 3-way with the lady mentioned above and my best buddy. There wasn't any 'real' penetration, but things got kinky enough that I don't think it qualified as anything other than sex. And even if it didn't count, I still think of it as my first 'cause he was the first man I chose to go to bed with. It was also pretty awkward, but well worth it.