High blood pressure confusing.....?

ok so my systolic is usually 140 and higher *max being 168* and my diastolic is always under 80 my pulse is always between 58-63 i'm confused how my numbers are so high. I'm18 (19 in October) 5' 9'' weigh 166 exercise almost everyday for either soccer *at least 1 1/2 hours* or gym * 30-45 mins weights* i drink at least 10 cups of water a day * usually 3 liters* i never drink coke or any soft drink and i rarely eat fast food or out in general. So my question is why is my number so high and if you could give me any tips to reduce it. Thank you for your time