Progesterone acts in conjunction with estrogen and whatever androgen blocker that you're taking to stimulate breast growth. It's pretty much a coin toss, medically, as to whether you'll see results or not by adding it into the regimen. Without the other two, obviously, there won't be any growth but you already knew that.
All that said, development is a mixed bag. You can pretty much guess that you'll be about your mom's size minus one cup size due to the larger area in the chest to cover with mammary tissue. It's not a hard and fast rule but it's a good general guideline.
For timeframe, everyone's development varies but the general rule is that the first year, things go quickly. You'll know that things are happening because they'll get reallllllly tender around the areola and you may or may not feel twinges of discomfort, itchiness, or sharp aches when they start developing in earnest. It took about eight weeks for mine to start doing their thing but they're still growing very slowly even now at a few years in.
Give it time, chick, this is going to be a long ride and there's a lot to it. Concentrate on the day to day business of living life, working through your internal journey, and working through your relationships with others. I know that the pace that things happen at isn't always super fun to deal with because you want it all right now but, yeah, it'll happen in its own time.