genetics. I regularly get quoted as 24-28 and I'm 34 in a few months. Not trying to flex as I've been fighting alcoholism and drug addiction on top of a nearly 10 year span of MMA training with over 30 stitches around my eyes, a badly deviated nasal septum from 100+ bloody noses and countless black eyes, some of which closed my eye completely. Then there's cauliflower ear and a couple of hematomors on my cheek, nostril and both ears.
I ran my body into the ground with training, very little sleep, sun exposure (Australia will toast white skin) and the aforementioned addictions that should have ravaged me more than I look. But I have no balding, no grays and I eat almost a predominantly meat, veg and fruit diet. Maybe that's what saved me, but in most part it was genetics. I have thick skin on my face (no laugh lines or crows feet), I moisturize and tone daily, and generally do all the girl shit to keep the skin on my face somewhat non-fucked-up looking.
Then again I worked with a guy two years younger than me that I would swear was a decade older. He was badly balding, had noticeable wrinkles and was hairy as a fucking dog. Merge that with wrinkle prone skin, and you can't help but look above your age. He was an asshole so maybe that's karma coming back at him.
In the end, you can't fight genetics.