I say k-girls in this business for the most part are exceptions too. If they look attractive i don't really bother with there age. I'm just fascinated.
Self selecting too, as only the women who reasonably enjoy the industry last more than one trip. With the constant moisturizing from shower routines, skin care routine (you can feel the serum reapplication), the relaxation from orgasms, etc. All the elements that are proven to keep people looking youthful.
Age estimates are more like an eval of bone structure, vibe and number of wrinkles. As some women just have auntie-leaning bone structures, while others are model-like, as an imdb deep dive into korean actors will clearly show. An example being the main women in the drama "thirty-nine", who are all actually 39 and look very different, yet still able to play flashbacks to their 20s in bright k-drama lights. Less hot women can definitely pull it off in bedroom red light.