I'm 6 feet tall. I owned a 17" regular mountain bike and it seemed to fit me just fine, now I'm about to a buy a 29er bike (doesn't that make it even bigger?), and every single person I've talked to is still saying to get a 19". Is this necessary? Is it that big of a deal? Wouldn't I be absolutely fine on a 17" 29er at 6 feet tall?