Everyone is different hon so there is no real answer to your question. Yes, your boobs will probably get bigger (ESPECIALLY when your milk comes in!) but how big and for how long is anyones guess.

I was a 12c - I had great, perky boobs pre-pregnancy (I've only appreciated that since DD stopped BF ) and only grew to a 14DD while pregnant and while feeding. I quickly went down do a 12D while BF and was back to my 12C not long before DD's first birthday. Everyone is different. I have to say though the 'milk has arrived' boobs are amazing! I'll be taking a photo with our next baby