Is hemoglobin with the number 17.4 high for my age? if yes, what's the solution?

Barely above normal: Your hemoglobin is just above the upper limit of normal. If you were dehydrated when the specimen was collected, it may even be in the normal range. Next time you are scheduled to have your blood tested, make sure you drink enough water before the test. Fasting for blood tests does not mean not drinking water. See this site for more info. http://www.nlm.nih.gov/medlineplus/ency/article/003645.htm.

Borderline high: Your hemoglobin is within high normal range. There could be multiple causes, including dehydration, heavy smoking, living at high altitude, blood disorders, etc. Your doctor would want to evaluate this further in order to make the best suggestions for you. Your solution now is to see your doctor about it -- and in the meantime at least drink plenty of water. http://tinyurl.com/mvppgm7.