Answer:it is normally considered bad to be above 90 which is why you should contact a doctor to see if you have tachycardia (increased heart rate). but dont jump ahead of yourself because your heart rate may differ now if you notice that 121 is a normal heart rate for you then tell your parents to call the doctor becauseyour heart rate might differ from activity. Have you been walking around? Are you out of shape? Are you a male or female?My suggestion before you make any rash decision do this simple thin sit for ten minutes relax the take Your heart rate again if its lowered then you should be fine do it every 10-20 minutes (make sure you are not constantly getting up and down) for the next hour or 45 minutes your choice and see what the difference is.......