Give the guy a break, he aged at least four decades on only 19 years.
When you look at the ages of the actors who played him and consider that people’s skin age faster under harsh sun, the discrepancy shrinks. If you make the Clone Wars longer (three years is too short for such an epic, galaxy spanning, Republic destroying conflict) Owen and Beru’s ages make more sense in the PT and their apparent age in Ep 4 no longer is off at all.
Granted people can look older than they are, but Ewan McGregor was around 35 when filming ROTS, and Alec Guinness was in his 70s when filming Star Wars. Sure, actors don’t always play characters that are the same age, but unless it’s obvious through makeup or exposition it’s a good metric. I could see McGregor being as old as 45 in ROTS and Guinness being as young as 65, but it strains credulity:
I also can’t help noticing that Guinness’s nose and ears are proportionally much larger than McGregor’s, and this is a characteristic not of harsh environments but of advanced old age which only gets more pronounced in Empire and Jedi.