I recall back in the 80s reading interviews where the Stones were asked if they were too old to continue because they were 40. Rock 'n' Roll was a new thing in the 50s and it stands to reason we all got older. It was no longer something for the teen-age (sic). I think across rock, blues, country, soul, folk, jazz etc, age is no issue. If you were trying to be in a boy band, I'm sure there is an age limit but personally speaking, at 45 I'm a better player, having more fun and less stress than the 22yr old version of me.