Is this normal

I'm 17 and in a month and I've been a small B cup since puberty and they weren't super.....perky but they weredecent. So like 2-3 days ago I looked in the mirror and they seemed to be bigger and when I touched them they were very firm. ( the right more firm that the other) so I question is ...is this more like  I thought they would be done growing by now and I know I'm not pregnant. Thanks on advance