I am over 50 With a 30" DL & over the years my DW has varied between 60 lbs & 70 lbs for a compound bow. if I have been away from shooting for a while 60 lbs has seemed like a good starting place for me. How aggressive the cams are are a factor as well. Currently working with a CDT at 70lbs. Started this season after a laugh brake away with a mild 60 Lbs on an older Pro pro-tec & worked in to a 65 lb Carbon element & progressing further with the CDT up to 70 lbs.
I can be a speed freak though I don't need to be. When I am up to it I do like the speed.