Definitely not too young for night terrors IMO. One of my closest friends son's would often wake and cry out. I remember my mother telling me I did the same. I think its similar to sleep talking, some kids do it and others don't. If it was a sudden thing and you had noticed a change in behaviour I might be concerned it was to do with something that was upsetting her on a day to day basis. But if you are concerned get a second opinion, trust your mothers instinct. Does she seem to be a happy child in all other aspects?

*hugs*
Cailin