In addition to the late '70s storyline of Magneto being de-aged into infancy and then re-aged to his physical peak, he was also killed and resurrected very strong-looking during the Krakoa storyline just this past year. Between that and his ability to control energy, he has an excuse to look 30-ish forever. (In "X-Men: First Class," Sebastian Shaw even mentioned that as a welcome side effect of his own powers.).
And he is not out of place alongside WW2-era Captain America, Red Skull, Winter Soldier, and Sunfire, Vietnam-era Punisher, Civil War-era Wolverine and Sabretooth, and ancient Egyptian Apocalypse, to name a very few....
And he is not out of place alongside WW2-era Captain America, Red Skull, Winter Soldier, and Sunfire, Vietnam-era Punisher, Civil War-era Wolverine and Sabretooth, and ancient Egyptian Apocalypse, to name a very few....