To give the shortest explanation, I finally asked and learned that S does not return my crush. Somehow I was expecting that...
Our friendship appears to be relatively unscathed (if I may venture such an appraisal three days later), which I am glad about. I'm trying to hide disappointment now though, and frustration because I'm still attracted to her but have to stop hoping.
I did talk to another friend of mine, D, a few days before this, and she told me something that has been comforting... she said there'd be someone for me in college. (College is a month away.)
Still, if only "someone"s could seem as real before you meet them as they are when you fall for them.