Gina, I've been wondering about something and you seem to be the person to talk to. I have recently become involved with a boy who is quite smart. I think that I've been trying to be smarter to impress him, which isn't necessarily bad, but it made me think. If making yourself dumb for a guy is bad, then how is what I'm doing good? It's also possible that I'm just over analyzing things and I should be happy to have someone so awesome like me.
The way I see it, you want him to like you for who you are. If you're putting up a front, you won't be able to know if he likes you or the mask. However, if you're actively learning new things, and by extension expanding your mind and bettering yourself, that's a different matter entirely. As long as you stay true to yourself and your happiness, I don't see a problem.
There's a weird thing in romance culture about finding someone who loves you just the way you are, but I don't really agree with it. Relationships are about growth and change. People don't remain stagnant. We live. We breathe. We move. We grow.
The only thing that might be problematic is if you're doing it solely for the sake of impressing him. If you're really learning and growing, that's great, but you shouldn't act a certain way just because you think it's what he wants to see. Never smother your true self for the sake of impressing someone else.
Grow with him. Change with him. But make sure you're changing for you and don't pretend to be or do or like anything that doesn't ring true in your heart.