The relationship between the speed of Time and one's age

In my life, time seems to go quicker the older I get. At Secondary School, a week seemed like a month. I honestly thought that I never was going to leave, but the day did arrive. In my late teens, a week seemed like two weeks, but since I got to about the age of 22, a month seems like a week and a week seems like a day... perhaps there is some mathematical/Scientific reason for this.. or is it just life? The older I have got, the quicker time has passed by. I dread to think what speed time will go at if I am still here at the ages of 80 or 90.