As we age what we lose in IQ which is essentially a measurement of processing speed and ability to manage abstractions, we gain in Wisdom.
I think you are right. I sometimes wish I could go back to being an 18 year old but not be as foolish. It is a miracle that I survived and I really mean that.
I once came so close to a non survivable accident that looking back, there is no way I should have dodged it but somehow at 110 mph, I did.
My parents would have had a fit if they knew how much I liked to race cars often racing long distances on public roads.
If I could go back would never do some of the things I did. An 18 year old thinks he will live forever.