Well, I was practically broke when I was 18 - I didn't get a job till I was 19. I got unemployment benefit but it wasn't much and even in those days they were doing all they could to make my life a misery and snatch it back.
At 30 with a million I could probably have quit my job and been rather happier. I suppose that kind of money in those days could have set me up economically for life, and without the job to stress me out and take up my time, I might have been relaxed enough to make some better life decisions. As I'm 69 now, the extra 39 years of life would be nice too.
But the OP didn't specify whether we'd get to keep the knowledge we've acquired in the meantime. Knowing what I know now would make a big difference. A lot depends on how old the individual is now - obviously to a 15-year-old there'd be no experience to keep. Anyway, I'll take 30 and the million, regardless of the experience thing.