Why hasn't she accepted my Instagram request?

[211]

So I've been sitting next to this girl, we talk everyday in class. And I could say we have a decent friendship. Sometimes I catch her looking at me from the side of me, which sort of makes me thinks she likes me. I mean everytime we talk, we make excessive eye contact, & we like to help each other out. Our class is science, anatomy. Recently we checked each others blood pressure but her heart beat was pretty rapid. But anyways I was wondering why she hasn't accepted my request on Instagram -_- . She changed her name too but she hasn't accepted nor declined it. It's been sitting there, and I don't think I did anything wrong? She still talks to me like nothing? Ugh. I just need an explanation lol.