Iin I want to change my name at 40?

It's your name. Do it. People will adjust. I've gone through a name change too. Better to do it now than regret not doing it. You can try just going by this name for a while before legally changing it. You'll feel better being called by your true name (Jenny rose) I had changed my name in my head years before I came out with it and being called my new name feels so right and satisfying.