To Be Young Enough to Know It ALL, Again

Because I am the mom of a teen-aged daughter and volunteer as the co-leader for her Girl Scout troop, I spend a lot of time around kids between the ages of 13 and 18. I've realized something over the last few months. I want to be young again! Not just young, but young enough to know it all!
Yes, I wish I was young enough to know it all again! I want to be:
Young enough to think I had all the answers to every single one of life's questions, but without the knowledge that I didn't even have all the questions yet. That's when life was full of possibilities. I could change the world back when I knew it all!
Young enough to think people in their 40's were so out of the times that their advice couldn't possibly have any relevance to my life! If I was that young again, there are a few things I'd do differently this time around.First of all, I'd actually LISTEN to those 40 + yr-olds because now that I am one of them I know they actually do know what they're talking about! And they know because they've been there, done that and learned a valuable lesson from it! Yes, if I were young enough to know it all, I'd know better than to ignore that sage advice!
Then I'd get my degree, work 2 or 3 jobs if I had to in order to pay for it because it is more valuable than I realized back when I knew it all!
I would also figure out a lot earlier that other people's opinion of me really doesn't have to affect my life in any way. Someone doesn't like what I do or say or how I look or dress then that is their problem, not mine. A wise older woman once told me "if it isn't your puppy, why do you keep feeding it?" So many things I worry about turned out to be someone else's puppy. Once I started letting them feed it, my life got a lot less stressful!
I would also realize that not every comment is an insult nor is every question a judgment on my life. I'd be a lot less defensive if I were young enough to know it all again.
Yes, to be young enough to know it all, yet old enough to know better! That would make me just about perfect!