What is 'normal'? When you can answer that you can answer your own question.
The chances of heart attack
at your age are slim, assuming you are a 'normal' person. In other words, as long as you aren't obese
, do some exercise, eat sensibly and there is no history of heart attack at a young age in your family, it's not something you should worry too much about.
As for being normal, back in the 80s one of my younger sisters (she'd have been 12 or so) was constantly worried about the threat of nuclear war. So as I say, what is 'normal'?
Mind you, if that is all that you have to worry about in your life then you are quite a lucky person.