I have noticed a few difficulties while glueing the pieces together, I am still a n00b at this but I'd like to share them with you.
1- Check your helmet's dimensions and divide it into 2-3 pieces.
2- The eyes part is not necessary you can cut them off.
3- Make sure you got clean cuts and trim the excess with scissors if necessary.
It seemed to me you started off with a good Top-Head piece but screwed up on the cheeks and the jaw, also Don't try to stick with the pep model 100% the 3D model ( as I understand ) doesn't take into count the little creases you get while bending the paper, it can determine the size of the paper but not the thickness of it.
So make little adjustments as you keep glueing , cut some excess and re-apply glue.
I suggest you resin this just to get the feeling of how to deal with resin at the least, it takes practice.