Just leave it alone unless you're planning to breed her.
I had a caslick done on my mare midway through her 3rd year in the jumpers because she would windsuck on takeoff and it would distract her for a split second. A clinician pointed it out to me and suggested having it done. It didn't make a huge difference, but it did make enough of one that I've always been happy that we did it.
__________________________________ Forever exiled in the NW.