Another 25 year old with a similar situation! My initial smear results only actually came back as mino changes, so thankfully now they test for HPV (positive) which booked me in for a colposcopy.
I wasn't worried at all as they were only minor changes, then had 2 punch biopsies taken at the colp. These then came back as CIN3 severe dyskaryosis - at 25 with a low grade smear a massive shock!
Coming from my experience, every women is different and will react to/handle treatment differently. I felt the colposcopy wasn't much different to the smear, a bit more clinical and fancy equipment but only because of how detailed it Is! If you have punch biopsies taken this is uncomfortable and not going to lie I freaked out at this. Some light bleeding and cramping for his a couple of days but wouldn't feel bad at all if I had to have it done again.
This forum is such a great place for us to be able to chat and share experiences. No matter how many people tell you it will be fine and they have had it done so you will be fine - doesn't change how you are feeling! It's a massive shock for anyone and especially at a first smear. I'm so grateful that all this is in place and of course is a preventative, but still can be a worrying experience - we're only human after all!
Really hope you get all good results! Xx