Thanks to Eric, who commented a few blog posts ago, and other folks who have mentioned April 15th as the date we applicants have to make our final decision. It's nice to know we have some rights, which I somehow didn't know before.
Oklahoma State, as they've been from the very beginning (which is another reason it's going to be very hard to say no to their offer), was extremely nice about letting me know the deal.
They wanted me to let them know by March 13th if I could because if I don't let them know early enough, the fellowship money they're offering me gets absorbed back into the college—not necessarily the English department—and they may not be able to offer it to other applicants.
But they understand my situation, and I'm sure I'm not the only one waiting to hear from other schools. With five schools to go, the last thing I want to do is accept Oklahoma State's offer in writing and then end up telling them, "Sorry." I would never want to do that to anyone, and this way I don't have to.
I really, really can't wait until I know where the hell I'll be finally. As much as July and August are going to be rough months, I'm excited to get back into it all.