I have a blood pressure of 146/90 and pulse of 31, is it possible that i could end up having a heart attack?

Pulse of 31 doesn't mean all that much. The fact that your blood pressure is 146/90 even with a pulse of 31 means that your heart is able to maintain blood pressure even with such a low heart rate. Main thing is that you really should see a doctor and see if it's necessary to go on long term anti-hypertensive medication. 146/90 at the age of 17 is really high. I don't know if it's necessary to go on medications immediately, but you should definitely get routine blood pressure tests to make sure it's not rising any further. Any higher and you'd end up needing to start on a diuretic like HCTZ or an ACE inhibitor.