Crushes and "butterflies"

I see references here sometimes to people having "butterflies" when around a crush. I definitely remember my first crush, which was on a guy when I was 13, and I had that. I actually thought it felt more like going down in an elevator. I had it when I thought about the guy and I just kind of thought "well, this is fun, guess I'm growing up." He wasn't my age at all so I didn't really sit around having fantasies that we got together but I did want to be around him a lot.

There are a few things in my life which make me suspect I might be gay, which are mostly outweighed by reasons to think I'm not, and I won't go into all of that again here, but one of the things I keep thinking about is the feelings with that first crush, and remembering feelings like that for other guys and not the exact same ones for girls, and how it must mean I'm straight or maybe bi. (There are even more reasons to think I'm not gay... but this is still a surprisingly big source of confusion for me. Especially since I get a really similar feeling now, many years later, thinking about not being straight and being able to be with women, just in general.) Anyway I got the impression maybe other people had similar experiences and confusion, so I thought I'd bring it up.