Actually no-one has suggested that yet I was just looking at the images of Princess Peach costumes after seeing your comment and they can be rather cute.
However, not being all that familiar with the Mario game, I wasn't aware that it was a character in that game. Mind you, having not seen "The Matrix" I didn't know that "Agent Smith" (a nickname I got in the local photography/modelling community) was a character in that film. I fail sometimes when it comes to pop culture references!
I don't even know if she came up with that name based on the character or otherwise actually, generally when we're filling out the paperwork after their first shoot, I ask the model "what do you want as a stage name?" and they're often like "er .... um" and then say whatever first comes into their mind.