Hey, pick one :

I'll take the extended life. A billion dollars can't buy that.

I would be very wealthy and change all my broken relationships. My life would be completely different. I would say goodbye to my parents very differently.

I'll take the cash

there's no telling what would happen if I was young again

I mean the butterfly effect might have made things totally different and my choices wouldn't be guaranteed to be better.

If i could start over from age six with my current knowledge I'd be a billionaire at 20, and the richest man on earth by 50.

Decades spent watching stocks and technology would pay off.

billion dollars would give a better future than a future at 6 with all the knowledge

I rather restart at 6 so I could run away from more trauma that might be coming.

Let me restart. I don't need a billion dollars

This is easy choice — start over

Id probably take the cash

Honestly neither.

Restart for sure

Define your terms :
1) Does this mean going back to the year you were 6 years old for a complete do over or waking up tomorrow in a 6 year old body?
2) would I have to pay taxes on it? Would anyone else know I had it?