Thinking about my breasts...

I was wearing a C cup bra when I started high school. By the end of grade 10 I was endowed with a D. And graduation saw me with a DD cup.

I bought bras a couple of months ago in a C cup (the same size as when I was 13 years old) and I've noticed that I now have quite a bit of room in these. Is it possible that I may be looking at a life of B cup bras?

This just blows my mind!