This whole chapter was a big yikes on all fronts.
First, the girl goes a bit nuts.
Then the MC rejects her in the worst way possible - that kind of reaction can cause long-term damage to someone. I just can't not feel bad for her there, regardless of what she did prior.
And after that, he is confused about why his teenage body, which probably gets boners from looking at a curvy bottle or hearing the word boobs, got one from looking at a naked girl... And he acts like it's the end of the world... Just from that reaction, we know that mentally he's barely a teenager, let alone an adult ready to get into a relationship with someone who is in their mid-30s.
The premise worked when it was kinda joky, in a short-format manga kind of way. But if we are talking realism, someone who's 35 would have virtually nothing to talk about with someone who's 18. Unless they both like similar media, like games or TV shows, but that's just a filler. What else though? Will they reminisce in bed about the time she was his teacher? Please. After this chapter I'm 100% with Sensei - this guy needs to move on. Some might pull it off, but he is at least 10 years too early from dating in 30s.