Competitively, it is often better to be a big fish in a little pond than a big fish competing with other big fish in a big pond. Only the select elite make it in the big pond, where the other big fish would have done much better for themselves in a smaller pond.
It's hard to know, a priori, if you're more elite than your incoming competitors for the position, and its no doubt good to think you can win any position battle. But playing time is zero-sum, and someone has to lose. If you are truly elite, you'll be elite wherever you go. It doesn't have to be at a powerhouse school.
At their age, though, it's hard to ignore the glamor in an Alabama and think rationally.