This may seem weird, but a lot of people can smell changes in hormone levels, but never realize that's what it is. I can tell where my wife is in her menstrual cycle by smell. And I'm not making a misogynist joke, I mean it seriously, and it's there on her neck, her face, her arms, everywhere.
I can even pick up my own shifts, which aren't as big for a cis man compared to cis women.
So I'm not surprised you would detect a change after it hit a threshold for you. Nor that it took you a bit to connect it to yourself, and it being an attractive scent just makes sense to me.
It helps, like was already said by another commenter, that as you go through the process of changing your body, at least a small part of overall stress is going to change, which very much impacts whether one's personal scent is pleasant or not. It isn't just stress, any strong emotional state can shift how we smell; but stress causes a more acrid, almost chemical scent for a lot of people, and that's detected as unpleasant usually.
It's cool as hell tbh.