Hey T Bird! I thought I'd share my opinion on this since I was just married in June of this year, so all the stress of planning a wedding is still pretty fresh in my memory ;)
Now, one rule that you will start to hear a lot is "whoever has the money gets to make the rules". That being said, it sounds like your parents are willing to pay for (at least part of) your wedding, which they certainly are NOT obligated to do. It really is a gift from them to you, just keep that in mind. (Not saying that to be harsh at all, its just the truth!) So in your case, it is absolutely fair for your mom to insist that you prove to her the two of you can handle life on your own. After all, she is basically "investing" in your wedding, and wants to make sure you guys are taking this seriously (which I have no doubt that you are). But, since she is the one that is going to be paying for all of it, you really need to step up and prove to her that you two are capable of living on your own and supporting yourselves. She cares about
you, obviously, and just wants to make sure you know you're ready to make this big step!
So honestly, unless you are willing to fork over the money yourselves, you have to play by your mom's rules. And remember, you should be grateful that she is willing to pay for your wedding, many bride's (or groom's) parents don't contribute a dime.
If you want some more wedding advice, I suggest checking out the message boards on brides.com - they're very helpful!
"You cannot hope to build a better world without improving the individuals. To that end, each of us must work for our own improvement and, at the same time, share a general responsibility for all humanity, our particular duty being to aid those to whom we think we can be most useful." - Marie Curie
"The pessimist sees difficulty in every opportunity. The optimist sees the opportunity in every difficulty." - Winston Churchill