Wagtail
Horse servant
My 9yr old mare has a long mane purely because she's been a broodmare for the last 5yrs and I've only had her a few months and haven't done much with her. It will be coming off soon though, although I have to say it does suit her long.
I think she looks lovely. Though I think a short mane would suit her too. A short mane helps make a neck look bigger and I know you are working on improving her top line. When the mane is shorter, it will lifet because it weighs much less and so the top line is raised slightly.