In the turbo prop world, there doesn't seem to be an age bar on pilots. At KLM uk there seem to be a few grey haired newish F/O's on the fleet.
The larger carriers, such as Cathay and Singapore, tend to have an "age commensurate with experience" rider on their job offers. I.e if you're 35 they're looking for 5000 hours, rather than a CPL and 300 hours TT.