She, of course, deserve somebody who loves her and who she can love back. So you unhappy with perceived difference between two of you and it nagging you that you are less well endowed. Possibly she also more self-secure and more outgoing than you? Its like you feel that you not fit (yet) to walk alongside her as an equal. It problematic for both of you if you no resolve this problem, which lies with you. It definitely problematic for you because feeling inadequate is one of biggest threats to healthy man's ego.

FO advise to not think about what the difference IS, but about what it is you want to become and possibly how she could develop. You no can change the present, but the future still open. That mean there no need for you to break your head about the inequality between you.

Also realise that you are not alone. She is there, capable to decide for herself so please don't be so arrogant to decide for her what is best for her. It may look manly to sacrifice yourself for her wellbeing, but don't justify such plans/decision without her consent. Otherwise you just a pretentious asshole.