Should be fine
But in general, it shouldn’t be very uncomfortable. It’s only in very rare cases that a foreskin is too small and causes consistent pain during sex. If that proves to be the case with you, go see a doctor who will be able to help you solve this.
I did finally find an uncircumcised friend-of-a-friend who said it hurt the first time. But for him, it got better very quickly. He explained that when you are uncircumcised the foreskin retracts to allow the erect penis room to grow.
The foreskin moves back and forth during sex and the friction can cause you some discomfort but you will get used to it as your skin becomes less sensitive to this type of touch.
The use of lubricant will also decrease the intensity of the friction.
Try it out
Incidentally, you could masturbate and this could help you get acclimatised to the sensation. If you are still uncomfortable, or your foreskin feels too tight, then you could try applying a lubricant and stretching it slowly and gently with your fingers.
I think first-time sex is uncomfortable for many reasons: being naked with another person, having them see you mid-orgasm, the noises our bodies make, the smells etc. Our partners get to see us without artifice and that can be awkward.
I don’t know how to grade the pain or discomfort you may feel, but if it occurs it shall likely pass soon enough. Of course, if you wear a condom, it will protect you from disease, unwanted parenthood, and reduce the friction so it shouldn’t hurt at all ;).
Does anyone else have a better answer for our friend? Leave a comment below!