I see. Yeah, I like the idea.
Great, experience than...
I see a couple of options:
1) Hard way: Try to balance leveling up system, I found some formulas but those are not very helpful since they are written around monster level, not vs level of other character. If done this way, it may take a good deal of time to get this just right.
I did think about this and I can prolly make it work, but it is not gonna be easy...
2) Switch to a linear system, kinda lame, but will be a lot easier to balance, experience required for every level will simply be 1000 points, much simpler.
3) Leave D&D level up system but adjust experience gains according to level. Just as easy to balance as above but is less lame. One drawback is that girls of different levels will get more experience for doing the same tasks (like cleaning for example). Fighting exp gains will be mitigated by awards being based on difference of levels, similar thing can be done for other jobs vs clients with a bit of effort.
4) Last option I could come up with, is a mix, we use simple exp gaining techniques (almost linear) and make sure that the difference for required experience for next levels is minor...