Blood pressure 140 60 is this normal to my age i am 21 year old?

Top normal: Your systolic pressure (upper number) is top normal. Be sure you're fully at rest when you measure it, that the cuff is large enough to fit your upper arm, your arm is at the level of your heart, and that you're averaging at least 3 measurements - to be sure it's accurate.

High: The systolic BP top # is a bit high for your age group. THe Diastolic at 60 is okay. I would check it again later on not immediately after. Look into simple causes first like salt intake was your intake higher in the previous days and you are retaining water etc. I would expect 120/60 maybe 130/60 for you. If the top remains high see a doctor you may be developing hypertension