I'm 25 too, found CIN2 and had my LLETZ this Tuesday just gone.
It's honestly not scary at all. They give you an injection on your cervix, which doesn't hurt at all, but does make your heart race a bit, and then you can't feel anything whilst they actually do the procedure. It doesn't hurt at all. I had my LLETZ straight after my colposcopy, so the nurse went and brought my mum in so I could hold her hand through it- it really helped having someone there just to calm your nerves a bit. The nurse then got my to talk crap to her, which was very easy for me, and the whole thing was done within a couple of minutes. Honestly, the worst part of all this for me has been that I can't exercise for 2 weeks, it's all so quick and easy. I'm obviously only a few days into the recovery, but I took the evening to take things really easy, but was back at work the next day and other than a lot of disgusting watery discharge, I've been totally fine.
I'm sure you'll be totally fine too, but I totally understand the anxiety, I luckily only had a week between being told about my abnormal results and then having the treatment, and I would be lying if I said I didn't spend that week totally petrified. But I can tell you that there's nothing to be scared about, and while it's not the most comfortable thing in the world, it is definitely no worse than your colposcopy.
I'm currently waiting for my results, which has got me nervous again, but it's all the unknown more than anything.
I hope your LLETZ all goes well- I'm sure you'll be more than fine :)