What should I do if I hear a QT3.14 I have a crush on doesn't like to date and would rather focus on grades
It's probably not 100% true. People say this to their friends (and to themselves) to hide their anxiety over getting into relationships (I know because I've used this excuse many times before).
You shouldn't let this get in the way of asking her out, though. Just don't get too needy when you do get together, if she needs to study, let her study.