I don't have much experience with dating or crushes and I've yet to be in a QPR myself, but, well. It sounds like you and your zucchini knew each other fairly well prior to entering this relationship, which leads me to believe that she wouldn't have been friends with and entered into a QPR with you unless she did, in fact, like you as a person
Also, while again I have no personal experience, I am a bit of a Romantic who has read copious amounts of fanfiction (not necessarily the best reference, I know, but I promise its good stuff), and my understanding of crushes is that while they might sometimes be formed based on aesthetic attraction and a limited understanding of someone's personality, that doesn't last into relationships without said relationship falling apart. Your QPR sounds fairly stable other than this insecurity, based on what you've said, so I honestly doubt this is a problem.
In the end, though, I'm going to give you the same advice I give everyone who's concerned about their relationship - TALK TO HER
Communication is key in any relationship, and the fact of the matter is that if you can't trust her to tell the truth when you ask about these things, you have a problem - be it between you two or just flat out anxiety. If the former, being concerned with her crush on you may be the least of your problems, and if the latter, my condolences my dude, but that's something you have to work on yourself. But the fact of the matter is, you can sit here and worry and mull over her feelings all you want, but in the end all you'll have is your own conclusions. You won't know the truth about how she feels unless you ask her.
Hope this helps, and best of luck!