If there's a range of consistancy in your life, then it's normal for you. I'm 51 and my range has always been 90/60 - 110/80. Some might think it's low, but it has always been this way, so no medical care needed.
Your systolic number is normal. Your diastolic number is a low/normal. Systolic is your top number and your diastolic is your bottom number. I wouldnt worry about it though. perfect bp is 120/80 but who really is perfect?