I think it all depends on the type of riding you do, what you are after in a bike, features
and look etc.
My first HD I got at 47, a flstf- hind sight says i should have got a roadking then for the riding i evolved into doing and the comfort I wanted.
Currently 51 yrs and enjoying my 2011 RKC immensely.
First HD at 43, '01 FLSTF . . . quickly realized it wasn't what I wanted and purchased an '02 FLHR that I still have and love, but also picked up my '12 FLHX less than a week ago. Turn 54 in about 3-4 weeks.