And welcome to the club ;-) That really sucks, getting an abnormal result on your first smear. I made it to 44 years old and then BAM! Same results as you. I can totally identify with the OH MY GOD and getting into a complete spin over it.
Firstly, colposcopy appointments seem to be really quick. Mine was within about a week of my letter, though I delayed it by a few days as I was just finishing a contract at the time. A quick appointment is not a reason to panic btw, they havent done it because they think you have cancer, they will just fit you in as soon as they can.
The colposcopy itself is fine, kind of like a smear really, but just lasting a bit longer. The consultant who did mine was great and answered a lot of my questions, so don't be afraid to ask anything you need to know. There seems to be a bit of a debate about what a borderline smear means. Some people have been told it's the mildest possible level of changes; however my consultant said that it means that the results are abnormal but they can't tell how abnormal.
For this reason, they are likely to do a biopsy at your colposcopy. I didnt find it painful and it's done in a second. The doctor will ask you to cough as she does it and for some reason this stops you feeling anything. I asked my doctor how she thought it looked and she said "either CIN1 or CIN2" hence the biopsies.CIN1 will often sort itself out, whereas CIN2 rarely does. They want to confirm the severity as it it were CIN1 they would take a watch and wait approach but CIN2 they will treat.
You'll then have about a 4 week wait for biopsy results, and if it comes back as more severe than CIN1, they will offer you treatment, probably LLETZ, to remove the bad cells.
So you will be fine, really you will. The bad cells will be zapped and you can get back to normal. Try not to worry too much - the chances of it being anything worse are statistically small :-)
Any questions you have you can ask on here and someone will be along to help. This site made the difference between blind panic and relative calm for me, which considering I started all of this with a medical phobia too is quite some achievement!
Best of luck, hope you get your appointment soon