If I recall correctly, she's only had a few weeks to get used to the kilt. Don't despair just yet!

Optionally, you can try out the "cross-dressing" crack next time she dons a pair of slacks. On reflection, I'd save that one; but the idea is to let her see how it felt when she hit you with it.

It'd undoubtedly be more adult simply to tell her how it felt. The conventional wisdom is to use "I" statements & make it about how you felt, not about what she did or how she wronged you. If that makes any sense at all.

Mostly, give it time. Let her see some other men in kilts, particularly the heavy athletes!