I know this all too well. People think I'm some sort of snothead who doesn't deserve any of what I have. I might not deserve some of what I have, but that's because I haven't had the chance to prove that I do deserve it. AKA taking a class that I really like and doing really well in it. Which I will do next semester. Which I have done this semester (I hope!). You can just be yourself, and if someone thinks you're snooty, then make it clear to them that you're not. I hope this helps. If not, then I've tried.
-Me.
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I am hopeful that this is helpful.