astarbabyxox is a big girl, with such a lovely face. I wonder what her bra size is.
Perhaps the best person at the BEA for this kind of knowledge, Margaret, can tell us what it might be. 
Well, it could be a custom-made size, although based on the pics I can see of her, she’s probably in the 38-42” back range and possibly a K-L cup. But she could just as easily be a 40HH.
Like many social media girls, there’s some distortion going on in the way her photos are taken - she has a large upper frame/torso, and is very low-set/saggy - a lot of the emphasis comes from the overall size of her body, rather than her boobs being gigantic. And there’s not too many full body photos to get a proper assessment established.
Edit: I went looking for a few more photos and found a few “less clothed”, which gives me a better idea. I’d definitely still say somewhere in the 38-42” back band and possibly K-LL cup.