big boobed ladies - when did they get bigger?

I keep seeing people post about how much their boobs have grown and they're under 20 weeks.  I'm currently at 19wk and haven't had to switch bras yet but I'm wondering what can be considered normal when you're sporting a decent rack to begin with.    I've been a 34ddd for a while - have some of you ladies not grown much at all, not change until the milk came in after birth, etc?  I've definitely had pain/tenderness on and off throughout, just no changes in size yet.  Quite frankly I'm hoping I won't change much but haven't ever heard of anyone that doesn't seem to swell up like a water balloon eventually!