I know its a small consolation, but the problem is probably not you; its more that likely the guys.
If you are like most 21 y/o girls, you probably have a decent job, and have some $$$ set aside, as you have been working a year or two.
Contrast with the 23-24 y/o boy, who is just waking up to and looking for direction.
Sorry. We as a society have failed young women like you.