I took my blood pressure at my local chemist today it was 121/78

is it good or bad?
tell me what it means?
any websites that can help me know the range i should be in for my age? im 28 yrs old.

Its pretty much perfect ... 120/80 is the norm

Blood pressure: The blood pressure is the pressure of the blood within the arteries. It is produced primarily by the contraction of the heart muscle. It's measurement is recorded by two numbers. The first (systolic pressure) is measured after the heart contracts and is highest. The second (diastolic pressure) is measured before the heart contracts and lowest.

so what 's the big deal ? 12/7 or 13/8 are perfect.
you're healthy dear ;)