I'm a 21 yr old female who suffers from anxiety/panic attacks. during an attack my hr can get up to 150-160. is this dangerous?

Possibly: You should be in treatment and have an anxiolytic available to reduce these panic attacks. SSRI treatment and psychotherapy will be more beneficial long term, and then you can get off the benzodiazapines, thereafter. 150-160 is a good target heart rate when you are doing cardiovascular exercise, so you should consider that along with your overall health.