30+ weekers - question about chest growth

OCW2010

I'm being asked by one of my best friends to be a groomswoman in his wedding in October.   If all is going well (fingers crossed), I'd be about 30 weeks by then, I think.  I'm about a D or a bit bigger right now, and I'm wondering just how big I should estimate my boobs will grow until then.  

How much did yours grow from pre-pregnancy or first tri until the 30+ week point?

Thanks!