my sincerest compliments

The root of this post is a text-versation I had with a friend yesterday. I told him I got my test back in a class and asked what I got. I told him my score (which I am proud of, but not in a prideful sort of way) and that I was satisfied with it. And he wrote back "What!? That's amazing! Well done!! :)" One of my nightmares... (Just kidding, It's not that extreme. I feel like exaggerating today apparently.) I've always had a little problem when people compliment or congratulate me on certain things. Only some things. If you're complimenting me on my clothes, hair, or teeth (which I never get complimented on and I'm just fine with that! Compliments on my teeth seem a little weird. Thanks... I grow them myself??) then I'm fine with saying thank you, you're sweet. But what about when someone congratulates you on a good test score or grade? What do you say back?? I know you should say thank you, but I feel the worst when someone else gets a worse grade than you by at least a couple of
letter grades but still congratulates you. I think the root of my problem is ever since elementary school I've felt like I've been compared to everyone else by test scores and I hate to compare myself with others. So next time someone congratulates me on a higher test score or grade, what should I say?? I think I'm over analyzing now...moving on.