I make devo kids do this drill before they ever try a FHC:
stand in a stretch on the floor (arms by ears)
bend over and touch the floor with arms/legs straight
without bending knees, push up on toes and roll forward w/straight arms
through a candle position (or your legs will smash your face)
maintain straight legs
before your seat hits the floor, push down on the floor with straight arms
stop in a piked position with feet at head height off the floor
If you can't do this drill, then the FHC will still be a problem.
Besides the stretch into the fall, you are probably missing the candle-to-pike transition at the end of the FHC. To compensate, you bend your legs to create rotation.
Good luck