A lot of people (including myself!) seem to lose fat from the head down. So the face and then the chest are the first to show changes.
Unfortunately, there isn't anything we can do to change the way the fat comes off. Generally, it's "first on, last off" -- which means our problem areas are usually the last to go.
Lifting weights can build up the muscle in your chest that supports your boobs but can't increase or maintain their actual size because boobs are fat and tissue, not muscle. Darn it!
But the good news is that fat loss tends to even out in the end, so even if you feel disproportionate now, hang in there and by the time you reach your goal, everything should be balanced.
And welcome!