Bra size ?

I’m going shopping today for bras since one of mine broke and I’m wondering if I should be getting a bigger size because I’m 12 weeks & my boobs have been growing? Before pregnancy I was a B cup, but honestly a B is generous 😂 I can probably fit an A cup but I just like buying B because I don’t like saying I’m an A cup lol. My old bras have been fitting okay, they don’t feel tight or anything. With COVID and everything I can’t try on any bras 😕