Can I have sex and exercise?

Yesterday I started a length and girth routine, but I plan to have sex with someone in 5 days. I'm scared and hope not to injure myself, so I'm torn between continuing the routine and getting bigger in the future or postponing it to take care of my penis until that moment arrives. Won't the routines tire my penis out? I am virgin, my dick is average and I have the pressure to satisfy this girl, my life is a mess.