I'm a young woman who has never had children, and the first time I had it inserted was very painful but worthwhile. I had 2 Advil before the appointment to dull the pain. This time, 5 years later, I went with my fiance to have my old one removed and a new one put in.
Still worth it, but it hurt more than anything I've ever experienced. And that was with misoprostil (a cervix softening agent your doc can prescribe. It's possible that since I stopped getting my period after about a year on mirena (Wahoo!) the timng of the appointment was ppor and my cervix was more closed than the last appointment. Either way, I'd go in prepared for the possibility of it hurting a whole lot.
The practitioner was a seasoned female gynaecologist, just so you know

And cramping/bleeding wasn't too terrible afterwards, just a week or so of the bleeding a couple days of regular period cramping.