I can imagine a row if you just go and get it cut and then 'surprise' him.
I'd just talk it through with him, and tell him that's what you are going to do. There is an under-lying issue here - which will have to be dealt with at some time or other.
It just confirms how much is compromising about certain aspects of male/female relationships - that we end up playing roles that don't feel right or natural to the self.
I'm not really aware of the 'older woman short hair' thing...from what I see most women tend to cling to the socially accepted hair/clothes uniforms that they have been adopting since youth.
I first had my hair cut short age 9'ish - and loved the ambiguity, and thought it interesting that some people assumed I was a boy. I then cut it short for my 12th birthday - and loved the feeling of defying convention that elicited.
I've had it long, middling, black, blonde, purple, and all sorts in between, but always have returned to short. It's just me. I'm quite 'shapely' - but do have a long, slim neck, nice ears, and nice shoulders - so have always carried it well, I guess. Don't feel the need for big earrings or anything - but do like pendants and stones.
I like the not-conforming bit the best, though - and for me having short hair says "I'm me". "I am my own person". I don't exist just for men to fancy me. I like the feeling of liberation that comes with that.
I'm 53 now, but most people are surprised when I say that. The short hair and the feeling of personal integrity that helps to solidify, is a large part of the reason for that, I think.
Hair is a very personal thing for most people, and a large part of how we express ourselves and our values.
Do what you fancy. Your husband sounds young and immature in certain respects, but you obviously love and value him. He should also love and value, and even desire you, with short hair too. If he doesn't, then I'd say that there is an issue there which needs exposing.