That should be 15-20% get genital warts.
Welcome back to the forum. Thanks for your question.
Probably around 90% of all sexually active persons get genital HPV at one time or anothe (often several times), and probably about 15-290% or more get genital warts as a result. Although condoms reduce the risk, even with condoms there is plenty of opportunity for skin-to-skin contact -- so even consistent condom users usually can expect to have one or more genital HPV infections. While your intent is admirable to not be sexually active until you are "in a relationship", that strategy won't have much effect on your risk of future HPV infections, which are equally common (or nearly so) in people with few versus many sex partners. As for timing, warts generally become visible 2-12 months after exposure, with an average of 6-9 months.
To your specific questions:
1) The reactions to treatment are highly variable. Warts often just shrink away with little or no scabbing.
2,3) You'll know the treatment works simply because the visible warts disappear. (This isn't rocket science!) But most patients treated with cryotherapy (freezing) require more than one treatment, sometimes several. If after 1-2 weeks the treated warts persist at all, or if you are uncertain, return to the dermatologist. And of course if new warts show up, which isn't rare in the first couple months after they first appear.
4) Although warts themselves generally clear up promptly with treatment, it's really not possible to know when the underlying HPV infection is entirely gone. My standard advice is that once the warts are gone for 6 months, with no new ones appearing in that time, people can consider themselves cured. But there are no firm data on this, which is why you'll see different estimates from equally reliable sources.
I hope this has been helpful. Best wishes-- HHH, MD