Milestones of time

As far as I can see our life is a rapid thing. Sometimes I feel time goes by too fast. I've never thought I'd become a mother, get married and finish university. It seemed so far when I was a little girl. It seems to me that a person's life is a kind of a bubble - the more little you are, the more space is around you; you grow older and the space shuts up like a telescope.
Also it's evident that time flies when one of your friends has a baby. You just saw her pregnant and, oops, her baby attends kindergarten! Children are like milestones.