It could be considered low, but low blood pressure needs to be considered in terms of the person - if you're a young, fit person, your blood pressure is likely to be lower than most.
Remember that blood pressure, particularly around and below 100mmHg is hard to measure and machines (particularly those that aren't calibrated regularly) are not the most reliable.
Independent of that, if you are feeling faint regularly, it's probably worth a visit to your GP.