21 year old female has High BP

I am a 21 year old female that is not overweight (5 6 130lb), and who exercises regularly (4-5 days a week). However, my blood pressure is about 140/90 (measured several times at the office) My doctor says it is even higher for me because I am so young. He told me to measure my sodium intake on an average day. After a week of monitoring it, (not eating any differently) I found I rarely go above 2,000 mg a day, average about 1,800 mg (you should not go above 2,300-2,400) Is my case strictly hereditary, since I practically do everything possible to not have high blood pressure? Should I inquire about prescription drugs to control this? What else can I do about it? Will it just keep raising with age ? I am especially concerned since my father died of a heart attack at the age of 41. No and i have never even tried a cigarette in my life! Don t drink either, if that has any effect