Everyone is choosing red because they think they would be rich, but would they?
Imagine having the knowledge, that you knowingly stepped back in time, and all of your memories are now not real. They won't happen again unless you actually act exactly as you had before. No one believes anything you say because you are 6. You're forced to go through school again at 6.
Let's say you use your genius to progress quickly through school. Those sorts of kids become famous prodigies. You would end up on the talk show circuit with Ellen.
You would also know way more about your parents than you should at that age, and cause familial issues that would land you on Dr. Phil.
Imagine how torturous it would be to relive every moment, not being able to convince anyone of anything due to your age, unless you give up the fact that you were somehow sent back in time and know the future. Would you be able to convince your family without going insane? Would any government agency take qcute interest in your foresight? Imagine having to keep a level head while also going through puberty a second time.
How much will your presence affect the timeline? Maybe your first big move to get rich causes all subsequent moves to not exist. Maybe your parents hate you. Maybe it's chaos theory. Maybe you end up taking a path away from opulence and become an addict due to the constant anxiety, regret and boredom. Maybe you become a nihilistic mess that drives you to a worse life than you had before.
I'd take the definite of $10M. I know what I would do with it right now. I know it would be good.
Edit: a downvote without a reply telling me how I'm wrong is really an upvote.