You're only mismatched if you think you are.
Women are attracted to men for all sorts of reasons. Yes, your physical appearance plays a part in that. But humor, sincerity, intelligence, success, and style are all integral to your overall appeal.
Look beyond leagues, and stop limiting yourself based on invisible markers. She may be way hotter than most women you date, and you may be much wittier, or just plain smarter than the men she's dated in the past.
At the end of the day, realize you have no idea what her type is, or what she defines as desirable. Plenty of women like chubby guys, and just as many prefer scrawny, awkward guys. In short, your chances are just as good as any other guy's.