Higher cholesterol can affect us at any age because there are two kinds of cholesterol: endogenous cholesterol is made by the liver in the body, which is used for many biological processes, such as lining nerves, serving as a precursor for other hormones and providing cellular structure which is a hereditary/gentic based level of cholesterol whereas exogenous cholesterol is what we get from the foods we eat and can be controlled by diet. There is no way to test as to whether the cholesterol is which type, only making changes to the diet to see if there is improvement will know if it is one or the other, and if not helped by diet, medications are typically needed to control endogenous (and exogenous) cholesterol.

It is important though to treat and let it left to go unchecked either by changing the diet and possibly adding medications as you have read about the risks. It is great not only that you are doing research but that your doctor is staying on top of it. Follow-up monitoring is important as well. Perhaps these links for lifestyle/dietary guides might help meanwhile and know that it can easily be controlled, not to worry.

Cholesterol: Top five foods to lower your numbers - Mayo Clinic
11 Foods that Lower Cholesterol - Harvard Health Publications
Cooking for Lower Cholesterol
https://www.nhlbi.nih.gov/health/pub...l/chol_tlc.pdf