Fifteen years ago my father had a heart attack. His Canadian cardiologist said that his homocysteine was the highest ever seen in the lab in Western Canada where his blood was tested and that the condition is genetic. I took myself to a cardiologist immediately and found my level of homocysteine was as high as yours is. I'm still here and my homocysteine is much reduced, but I take large daily doses of folgardrx. I've also had more extensive tests that show I'm hetrozygous for MTHFR C677T. I recommend that you see a cardiologist regularly and while you are at it see if you can get diagnostic tests such as the ones offered by Health Diagnostic Laboratory Inc. or the Berkeley Heart Lab to see if you may have other underlying conditions that can affect your risk for heart disease.
Lots of things can elevate homocysteine -- vitamin deficiencies (specifically folate, vitamin B6, and vitamin B12), cigarette smoking. It may be worthwhile to take a multivitamin and stop smoking (if applicable) to correct for either of these two causes, although the evidence isn't clear as to whether increasing homocysteine levels changes your risk.
High homocysteine levels are associated with an increased risk of heart diseae, stroke, and blood clots, but they don't increase the risk as much as other factors such as diabetes, high cholesterol, high blood pressure, and smoking. It is impossible to predict how the homocysteine will affect you, especially in the next 5 years, but cardiovascular disease is more common as we age, so at age 23, your risk is much lower than in someone older. However, knowing that it does put you at increased risk (in the long term), you should pay attention to your other risk factors and try to modify them -- exercise, healthy diet, weight loss if needed, cholesterol control, blood pressure control, diabetes control etc.