Boobs growing...

So I’m 17 and my boobs haven’t grown in ages, they’ve been the same size for ages I’d just assumed they’d stopped growing, anyway, in the last like month and a bit theyve gotten so much bigger. I noticed just before my second to last and me and my boyfriend assumed it was just period boobs but that was ages ago and they’re still getting bigger!! Haven’t gone down in between periods🤷🏼‍♀️

Is it bc of my sex life? I’ve been w him 2 months and had 0 sex life befote him so could it be that? Someone explain lol