What are the chances of a 23yo female to have a heart attack or to die suddenly?

Rare: The incidence of coronary artery disease in healthy 23 year old women is extremly uncommon. Heart disease is a disease of the middle aged and elderly. There are some forms of congential heart disease and if you have a family history of early coronary artery disease or are having what you feel to be symptoms of CAD see your doctor to discuss.

Rare but: Heart attacks in people under 30 are rare, but sudden cardiac arrest can occur with cocaine, alcohol & other recreational drug use. Also people with a congenital heart defect (which may previously have gone undetected) can also die from these suddenly. Here is an article addressing the non-drug causes: http://tinyurl.com/le4tecc Info about drugs & alcohol's effect: http://tinyurl.com/lgeupxw