14 year old female diagnosed with POTS experiencing heart rate ranging from 44 to 204?

As in the title, I am a 14 year old girl, 5'6" (168 cm), 135 ish lbs, diagnosed with POTS. My heart rate when I'm asleep average in the 40s to 50s, and during exercise can get as high as over 200 bpm. Anyone know if this is normal or if I should be concerned?