Of course. My dad looks like he's in his late forties and he's 64, so I'm not saying that youth is solely for someone who has had cosmetic surgery. But some people, like my youngest male cousin (who is about nineteen) looks like he's on the verge of becoming a forty year-old minus some facial wrinkles because of hair loss that he started getting at age fourteen. So the appearance of age is dependent on genetics.
Yeah it might not have been the best comparison since actors usually get botox and expensive treatments. I wanted to compare him to my dad who's 53, but since no one here knows what he looks like, I went for celebrities. Also because he looks about the same age as those actors so in my mind that's just what 50-ish year old men look like.
But it's not just about senseis appearance though. He's retired! And people treat him like he's old. I mean he did say that he retired early but..... come on. Unless he has some type of illness that made him unable to work.
To me, it seems like the mangaka must be really young and just wanted an old character and though 50 sounded kind of old. Either that or it's a typo or mistranslation
wait.... he's 50? he does NOT look a day younger than 70. For comparison, Brad Pitt is 56. Robert Downey, Jr. is 54.