At what age is a person susceptible for high blood pressure?

Any age. I have seen blood pressure in overweight teenagers, and there are certain diseases that predispose to blood pressure becoming high early. In people who have strong family history, are obese, and are physically out of shape, it is not uncommon to see high blood pressure in the mid to late 30s. I find by the 50s, even some very thin and fit people can have high blood pressure.
Any age. Depending on risk factors. The risk goes up significantly with age especially age 50.