This is basically what happened with me and my female bestfriend when I was 17, she would always like and comment on my pictures on Facebook, we started talking but I've always been bad at reading signs, I really was just being friendly on some "she a cool ass female" shyt, plus she was a real life virgin and I avoided that shyt all through ages 17-20 (wasn't trying to pop any cherries). We became really close though, last year we were hanging out and she mentions how she really like me when we first met but I never made any advances toward her on any intimate shyt, so she figured I didn't find her attractive (I actually do, but not having sex, while I respect it, is a nono).
Another fail I had like that was in my freshman year of college with this one fine lil female, literally little like 4'11. I was 6'6 and I guess she died for tall nikkas. She would always compliment me, play with my beard, and make unnecessary body contact, but I didn't peep the signs because she looked super innocent. My nikkas came to visit me one weekend @ UTSA and they even were telling me "bro she wanna fukk you"; but I thought they were just forcing and she wasn't like that. Later found out she was a complete bussdown and fukked like 30-40 nikkas our first semester, sucks because I really wanted to fukk her too.
Til' this day I'm still pretty bad at picking up signs from females. I'm way better than I was when I was then, like instead of somebody having to peep for me or me realizing weeks or months down the line a female was trying to get at me, it's usually like a couple mins after the initial convo I realize it which sometimes gives me chance to redeem.