Where does the time go???

I went for a long walk today and wandered through the Woodland gardens in Bushy Park, tomorrow my niece Thea turns 16 and my eldest son turns 12 in a couple of weeks, here they are 10 years ago, it seems like no time at all...... the 'hill' leading up to this old willow has been run up and down by all the kids over the years, I remember when it was a hard climb for them and a fall could hurt, they have run up and down it rain and snow, summer and winter, now the girls have no interest in it and the boys run up it in 2 strides and climb the tree....