I sure wish I had known about money in my 20s. I made a lot of it, but I spent a lot of it. Didn't start saving for retirement until a year ago (I am now 33). My previous company had a pension plan, so I didn't worry about doing the 401k that they offered (with matching up to 6%--talk about throwing away free money!). Plus, I had a whole life insurance policy that I was told would accumulate cash value and I could tap for retirement. I think that was a big mistake with the whole life policy...I probably would have been better off paying that 60-odd dollars a month into a 401k. After holding that policy for almost 9 years, it has only $5000 cash value. I am no longer with my previous company, and after working for them 8 years, my pension balance is about $10,500. Not a whole lot. Now, I feel like I'm behind the ball when it comes to retirement.
And, let's not talk about the credit card debt I've dealt with through the years. I was able to pay it off when I got ready, but that was money that could have stayed in my savings.
Boy, was I ignorant about money! I cringe just thinking about it. If it were not for my husband of 2.5 years, I'd still be spending money like water and thinking everything is okay as long as I'm able to pay my bills on time, and put some in savings (which I inevitably ended up dipping into). I'm doing better now, though, but I've lost some precious money-saving years. Now, I probably won't be able to retire like I want to until I get well into my 60s!
And, I've still got a long ways to go. I now pay my credit card in full every month, but I'm still spending waaaay too much, so much that it hurts to pay the credit card each month and I end up dipping into my savings! I put around $2100 in my various savings accounts (brick and mortar, credit union, ING, 401k) each month, yet I end up withdrawing almost a third of that each month to help pay my credit card! So, I'm a work in progress...
Kudos to you young people who have grasped the importance of saving and investing at an early age!

I wish I were in your shoes!