Dangerously high heart-rate while excercising?

Hello! I am a teenager and was working out at Lifetime this morning. I started off with the eliptical, and worked at it for 30 mintues with 1-minute sprints every ten minutes. But I noticed during the usual pace, my heart rate ran around 186 to 195, and during sprints it peaked to 201. Is this unhealthy, or even dangerous? What can I do to reduce it, but still push myself?