I've had time pass very slow and incredibly quickly at different times as a child and as an adult. Time is an incredibly crazy thing to study. Some people do say time begin to speed up as you get older and older. Well, I'm 35 years old and I've experienced time slowing down as I get older in some ways. But not always. So, in some way, like you said, it felt like the summer flew by at times when I was a young boy. It depends on a few things but there were those times and it might be a question of how often time was flying by for me as a kid versus how often it was standing still or incredibly slow. I can't totally say which as it was always speeding up and slowing down at different times and it still does all the time. Every day it happens, an hour can fly away and then the next hour can feel like an eternity. I'm full of curiosity still because I'm still a child at heart.