I'm a lot bigger than I expected, and with developing lasting up to 5 years I can only imagine I still have a long way to go. For me I started on the pill and a AA blocker, and then 6 months later started progesterone. At 2 months I was an A cup, 3 months B cup, 5 months I hit a C cup, and at 8 - 9 months I hit a D cup. I'm currently almost a year in but if that trend is anything to go by I'll need a DD in a few months XD. I personally am wearing a 36D right now. I have decent cleavage, but that's mainly because I'm still rounding out. I'm the oldest out of my siblings and the women in my family are all around DD - E cup, so I could expect to hit somewhere between those cup sizes if not exactly the same size as them. I wouldn't get too worked up over bra sizes though because it's all relative anyways since bra size can vary from brand to brand, what the size is varies depending on where you're at in the world, and well a 36D and a 40D will be very different lol. If you worry about how they are developing and stuff, I would said do massage them because that's amazing, and take progesterone, but it might not be effective for everyone. But yeah.