Hi,
Fairly tough to bend any 3/4" material. How much of a bend are you looking for?
As any material bends, stresses are set up - on the outside of the bend, you have tension (tendency to tear the material as if to pull it apart). On the inside of the bend you have compression (it wants to crumple like accordion folds)
You could make kerf cuts to get a tight radius, but this can wind up looking "segmented". Another option is to use 3 layers of 1/4" gluing these together. Using hardboard ("Masonite") can be a lot easier.
3/4" of fiberglass sounds like too much work and expense, but if you want an extremely smooth finish, it would pay off in the end.
Good luck.