This is one of those things that will only be an issue if you choose to make it an issue. If you are insecure about it, that'll obviously manifest itself, which will -- ironically enough -- get her to thinking about your inadequacies as a man or as an earner. At which point, your paranoia has become a self-fulfilling prophecy. Just be cool with it, enjoy it, and it'll be smooth sailing. Just make sure she doesn't expect to play the totally "female" role in the relationship and be constantly wined and dined on your dime.