A lot of passengers don't bother getting BP at exactly the 24 hour mark. The only issue is if your flight has connecting or continuing passengers. Those passengers were able to get their BP 24 hours before their first flight. That may be a factor if you're flying from an airport that has a lot of connecting passengers. Baltimore, Chicago and Vegas are good examples.
edited to say I see you're from Maryland. All passengers who are connecting (or continuing through) at Baltimore will be able to get a BP an hour or more before you can. If you're stuck with a "B" it's not because other passengers beat you by a few minutes but because other passengers were able to check in two hours before you.