If i print my southwest ticket a few minutes after 24 hours before it will i automatically get class a?

There is no guarantee whatsoever. It is because the flight you are going on could be a connecting flight for other passengers, meaning some other passengers could have their boarding pass printed out when they first checked in which must be earlier than you do. You could end up with a B. If you have a connecting flight(s) too, when you check in, you get 2 or more boarding passes at the same time, but the 2nd or 3rd ones are being printed out maybe 28 or 30 hours before departure, meaning you're ahead of other passengers who have to wait until 24 hours.