I want to make it clear I’m not just speaking to underage/teen girls. Any younger girl, and this can happen to not that young women as well.
Just because the guy isn’t technically a pedophile, doesn’t make him any less predatory. When you’re in your 20s you may not be a kid anymore, but you’re not fully developed as an adult either. You’re still vulnerable to predators who have the advantage of more experience and thus tools you don’t yet have, in addition to the other advantage of power imbalance due to gendered relations.
A man who wants to be your mentor, especially if he says he wants to “shape” you or anything similar, is a man who’s trying to turn you into his puppet, to make you “develop” (be molded) into the girl/woman that serves his pleasure, even if not directly sexual.
There’s predators who get off on the intellectual performance of the younger female objects of their obsessions. There’s predators who get off on your social development fitting their not-necessarily sexual fantasies. There’s predators who get off on the idea of taking a depressed girl and becoming her “savior”.
There’s people who get off to feet and fucking statues, you best believe there’s predators who get immense satisfaction from mental games against vulnerable girls/women even if they’re not (directly) sexual. And even if those things aren’t sexual at all to you, it will fuck you up. Because you’ll know or feel that you’re being used against your will, that you’re not being treated as a human, you’ll feel trapped, you’ll feel controlled, you’ll feel hopeless and disgusted with what he’s turning you into.
It’s about control, it’s about possession, it’s about ownership of who you are, it’s about having the perfect doll to play with.
It’s about you becoming mentally, emotionally, intellectually, socially dependent on them. It’s about a boost of their egos.
Regardless of your age, but especially if you’re considerably younger than him, and you see signs of him being fixated on this, RUN AS SOON AS YOU CAN.