Like the above commenter said, if you were are still active in sports or fitness, like if you run a lot or swim, then a lower heart rate then the average of 70-75 range is totally normal and good. If you cut out caffiene and sugar, then seeing your pulse rate drop to a lower level is likely.
Generally, the lower your pulse rate, the more effectively you pump blood, your heart is very efficient from exercising. Some people just have lower RHR's then others. Usually for women, if you're in your sixties at rest, then you are in very good in terms of conditioning.
I used to freak out because mine was so low, high 40's low 50's. My cardiologist told me it was fine. I used to be very active and I would run 3 plus miles a day. Some people have low heart rates.Try not to stress about it.