I might have gestational diabetes does this mean they might want to deliver my baby prematurely before it gets huge?

Depends on control: If your blood sugar stays high during pregnancy it will create problems for baby. Baby will begin to to make its own Insulin & begin storing the excess as enlargement of organs and body size. At some point, baby may be to large to go thru your birth canal & c-section may be necessary. If you achieve & maintain good control, baby will remain normal & normal delivery may be possible.