I disagree. Just do this thought experiment. What seemed longer to you? Your senior year of high-school, or your freshman year of college? I bet the college was longer, even though by your logic, it should have been shorter.
I buy the "you compare each experience to your previous experiences" argument. If new experiences happen at a constant rate, that works out to simple ratios of time, eg. senior year of high school was 1/17 of your life, freshman year of college was 1/18. But new experiences don't always happen at constant rates: some people open up much more in college than in high school. Hence it feels longer.
But I do have a memory of my parents leaving me with my grandma once and telling me they would be back in 3 hours. I was 3 or 4 at that time and I remember thinking how mind-bogglingly long these 3 hours felt when they said it.
And, by the way, for me senior year high school seems the longer.