I always feel like whenever somebody is making the specific point that they are so much smarter compared to somebody else they are just boasting their own trumpet.
Maybe you are smarter, Maybe you are not. Who cares? Are you developed on an emotional level to a point where you can deal with both so called smart and so called dumb people?
If you stop thinking about how smart people around you are and start working with them you'll learn to get around through life.
If you like the girl, go for it. If you think she is not smart enough, let her go. But always respect people, because that is what they will remember about you.
And I personally learned that everyone you meet has the potential to surprise you because they think just a little different. Enjoy the variety, enjoy the challenge of communicating what you mean on different levels.