It is sometimes called witches milk...
I have a theory that lactation in trans girls is a good thing. Breasts are not fully mature until a woman has lactated, I think this is a good sign that your development is going to be good.
Hope they are not too sore hun! Mine still ->-bleeped-<-ing hurt sometimes 2 years on. But then they are still growing like crazy,
You might find if you hear a crying baby, or feel amorous or very emotional your boobs will produce more. They are amazing things our bodies.