Very, very disappointed actually.
When I was 12, I thought I was going to be a dentist, rich, and married, in spite of my desire not to get married. I seriously believed that if I stuidied hard and worked hard, while there would be obstacles, with enough perseverance, I would become a success at life. I wouldn't necessarily be millionaire rich right now, but I would be able to live a comfortable lifestyle and would be my way there.
At my current age, I'm working a dead-end job in spite of having a bachelor's degree in a lucrative field, broke, and perpetually single. Only the latter I really don't mind that much. You see I believed all that junk about how education and working hard will get you ahead. It doesn't. It's more based on luck and skill rather than effort and patience. If I saw myself at 12, I'd quit school entirely. I would be much better off if I had not decided to learn. Ignorance is bliss.