Well, some people have success with fat transfer, but that's a crap shoot and a bit of a radical solution anyway. Remember that we, as a group often have large rib cages. I, myself, currently have a D cup, but because of my chest (40") it looks like a B. I'm confident it will get there eventually and if not there are all the cheats cis girls use, push up bras, inserts.
How long have you been on E, Rebekah?