I was asking myself that question during the whole trip up and while watching the other two people on the flight go. I refused to look out any of the windows, despite my instructor's exhortations to do so. While we were shimmying up to the door (it's really hard to do when you're strapped to another guy's chest), my thoughts were a jumbled blur (most of the trip up was). I was starting to wonder if I could get at least a partial refund if I chickened out. I was trying to frame the question in the best way so as not to sound like a chicken as I'm sitting at the edge of the plane and my instructor, so unhelpfully nicknamed "Pancake", was getting us into the right position. I'm about to say it when he does his dastardly little trick and I start to scream like a little girl as the fact that I just jumped out of a perfectly functioning airplane has hit some primal, instinctual level of my brain...even if I haven't consciously realized I've done the actual deed. My eyes close. I ended up paying the money for another guy to come up with me, jump with me, and take pictures. You can see the abject terror in my face in the first few shots.

And then I opened them when I hit terminal velocity and...it was just...the best way I've ever been able to describe it to a friend is "Imagine you're on the world's biggest, tallest roller coaster, riding down the first hill with no cart." I'm absolutely terrified of heights. But there was something breathtaking about seeing the world from that high up. There's a notable change in the pictures at that moment - I'm shouting, but in a good way. My arms are out. I high-fived the camera guy, though he didn't get a picture of it. All you feel is the wind and the cold (it was fucking cold that day) and...it's really early in the morning and my words are failing me right now. It's an experience.

"Because I could." is honestly the best answer I can give to that question.

EDIT - Found the pictures. First one is a few seconds out of the plane, second was when I realized how much fun it was.