Low Heart Rate Causes More Condition_symptoms Fast Heart Rate Causes/Risks?

Fast Heart Rate Causes/Risks? - low heart rate causes more condition_symptoms

I am 19 years old, very active and have a resting heart rate of just over 100 beats per minute. Sometimes more, sometimes less. My weight is slightly below average, I'm 132 and 5'11. After reading a little about the causes of higher rates of heart I knew my body size can be a part of the problem. But I also know that a fast heart rate increases my risk of heart disease. Recommend to more exercise and see if it helps, or should I go to my doctor and see if anything else wrong with me? Thank you.