J.N.
My daughter was about the same age when she began having night terrors. With her I alway went in and tried to comfort her. Most of the time she would push me away while continuing to scream. I always just stayed in her room till it ended and she'd fall back to sleep. Your not supposed to try to wake them. From what I remember reading it not uncommon for them to be up to 30 min long. I hating not being able to help her. What did help was to not let her get overtired by bedtime. They always seem to happen when we had a really busy or active day.
Good Luck!
Jen