Talk to the pediatrician about it, but it's probably a phase.
My middle child went through this really bad.
Like sleepwalkers, don't wake your daughter if she's having a night terror! She'll freak out more; THAT'S scary.
Has she had any change in diet or schedule? My daughters main trigger is if she doesn't get enough sleep, like if she stays up 30 minutes past her bedtime (only happens at home though, not at sleepovers; she's 6 now).
My daughter started with night terrors, which went on from about 18 months to 3 years old, then it calmed down, then she started with sleepwalking around 4. Now that she's 6, sleep terrors and sleepwalking rarely happen, but it ALWAYS startles me, LOL!
My daughters 'grounding' is she holds up one hand and taps her thumb to her middle finger. It's so weird... but I've learned that that's how to tell if she's having a night terror or sleepwalking.