I wouldn't do threading with her to start. I've done both and threading is definitely much more painful than waxing. With waxing it's one shot - rip off the band-aid, so to speak. With threading it takes several minutes because they are essentially ripping out each hair individually. I know a lot of people who wax but can not tolerate threading, and I would imagine a child would be even more sensitive. Threading is more precise, but that's not necessary for the lip and certainly not for a 10 year old. It also causes me to break out, which waxing does not.