Legal SW connection time in BWI is 25 minutes.
We had a connection of about 30 minutes through BNA (Nashville) a month or so ago. I hardly ever check luggage, but had to this time around -- and I was so impressed, not only did we make the connection, the luggage did, too. The gates were literally across from each other, and boarding for the later flight had just started. (We had crappy BPs, though, so it didn't matter!)
And yes, as a PP said, if there is a minor delay that is in the airlines' control (ie, NOT your party stopping to use the restroom,) they will hold the connecting flight for you. If it's a major delay, they can put you on the next connecting flight, providing there's space. You could also try sending one member of your party on ahead to the gate to tell them you're coming -- not sure if that would work, but might be worthwhile if you're a party with two parents and small children, or similar.
As far as calling SW goes -- since it's a legal connection time, it's doubtful that they would change it as a courtesy. For a fee, yes, if there's availability. It's certainly worth a try if the later flight is something you'd prefer, but I wouldn't be surprised if they're not willing to do it.
Only major suggestion would be to sit near the front of the plane on your originating flight out of MCO. I would also try to make sure your carryon was a backpack or similar, so that you can strap it on and run if need be, instead of hassling with a rolling bag, etc. (I've had to run with rolling bags many a time and it's not fun! LOL!) If your luggage doesn't make it, they'll deliver it to your home later that night.
Honestly -- I wouldn't sweat it. The airline booked it, as a legal connection, so one way or another, they'll manage to get you (and your stuff) home. You're flying early enough in the day that they have plenty of time to do it. I would just relax and enjoy the fact that you don't have to drive it, LOL!