It would be wrong of me to say that someone of your
age cannot have a
heart attack, because it can happen at basically any
age BUT the younger you are, the more unlikely it is. Have you ever had any tests, such as EKG or Echo to ensure that you wasn't born with a heart defect? This is being taken more seriously in the UK now, children in many schools are given an EKG before commencing any physical activities. It's a good screening process.