Hiya, I only had my 1st smear test last year at 27, as kept putting it off, but have to say it was fine. Obviously, I wouldn't want to do it everyday, and it was quite uncomfortable, but didn't hurt at all and was very quick. I have to say I came out afterwards wondering what all the worry and anxiety had been about, and vowing to have it done regularly in future.
Think it depends on where you live and if sexually active, as to what age you should start having it, although the norm I think is from 20.