Can I take my vit c and zinc pills when I have a colonoscopy at 3:30?

Best to wait. I recommend waiting until after your colonoscopy. Delaying these for a few hours isn't going to change anything.
Neither . Of these meds cause problems if the dose is missed so better to follow the exact directions of the doctor performing the colonoscopy and take nothing by mouth for 4-6 hours before your procedure. Best to check with the doctor.