Their age is pretty irrelevant here. Yoel Romero is 41 and Fedor is 42. Think they both entered their fighting prime at the same time?
Faber had 40 professional fights going into the Edgar fight. Edgar had 24 in roughly the same amount of time.
It’s obviously not a certainty but I’ll just agree to disagree. I don’t think Faber at his peak loses to the best version of Edgar, not at 135 or 145. He had more power, arguably better wrestling—or at least close enough to negate it, and was the better athlete.
Faber via right hand and guillotine.