Can speak anecdotally here when I wonder if this is a self-insert MC, cause that is too relatable.
When I was in high school, I had my heart not just broken but trampled by preppy mean girls. I ended up cast into a crowd of misfits from that point onwards (though a lot of these kids were in a ROUGH straits at home, and I wasn't). Made good friends, but it permanently turned me off towards the pop girl archetype.
I don't think he's in love with her because she's beautiful. He's likes her because of her femininity and personality. It's something I saw in my wife.
My guess is that the reason they were never into each other before was because he wasn't socially capable of having friends at the time. In the flashback chapter, we saw that brief glance of each others' eyes through the glasses, seeming to indicate that they were there the whole time. If my intuition is correct, they would have been together much earlier if their reclusve phases were gone. That's the "debut" part of this story.