Be careful with this one, as it might result in putting off your relationship as well as your wedding date. But, if you really want the lady to pump the breaks on the prenup, you might just want to show her exactly what she's getting into. Once you get married, she's going to have to love you for "better" and "for worse," so don't be afraid to let her know what "worse" looks like.
If you've been extra-careful about your hygeine and you've been hiding those Star Wars figurines in your storage locker, it is time to let your freak flag fly. Perhaps to this point you have been fronting like you are about designer clothes and tasteful furniture because you aren't sure how she is going to take the "real you," so by showing her your less desirable parts, you might also cure yourself of your crippling fear of moving things forward.