Pretty awesome first time, to be honest.
I was on a cruise that was filled with retirees, which sounds like a bad thing but it really isn't because if there are ANY woman at all, there is far less competition.
So, I was 15 and a big 15 year old as I went into grade nine a year before at 6'1, 175lbs. I met this girl who was about 20 who assumed I was older than I actually was and apparently she was in vacation mode because after a few days of hanging out she figured sex was a pretty good idea. I had nothing against the idea, myself, but frankly when is the guy ever in the drivers seat?
I was scared out of my mind and that was when she figured out how old I actually was. At that point she took it upon herself to show me a few things. I don't expect I was the best she'd ever had but we did have a great deal of fun over the next few days.
Really nice girl, way out of my league.