Mail it in or drop it off?

Dropping my ballot off at the King County building means my votes will be counted today and included in the totals for the races and initiatives that are decided tonight. Mailing my ballot in means it won't arrive at the King County building until much later this week or early next—and then my votes could help determine the outcome of races or initiatives that are too close to call tonight.

I'm don't knowing what to be doing. Hep me!