The answer to your question is that it depends, so it is important to discuss your concern with your primary care physician
. Obviously, most people your age (especially female) do not have heart attacks routinely. However, if your bad cholesterol (the LDL portion of your cholesterol panel) is high enough, then you might be at risk of an early heart attack. Most people no matter how bad their lifestyle is cannot get their cholesterol high enough to be at risk for a heart attack in the 20s. However, there are genetic diseases that can raise the LDL levels above 500 and even to 1000. If your LDL (which should be in the 100s or lower) is very high, then you might have one of these genetic conditions. The first clue might be whether or not you have any close family member's that had heart attacks in the early years. If they did, then that makes a hereditary condition more likely.
The first question is whether or not your cholesterol is high enough to warrant medications. If your LDL is less than 160, then your risk of heart attack at your age would be minimal. If your LDL is in the 200s or higher, you should consider getting treatment. I suggest you schedule an appointment with your primary care physician to have this conversation to make sure you don't put yourself at risk for a heart attack.