Joining a 48hrs team is a great way to get to know people and to get experience with timepressured filmmaking. Since you don't have any experience: be prepared to do simple stuff that may be a bit dull, but is essential to the progress nonetheless. You make sure you also get to see the shooting/editing.
You mention After Effects.
AE is a great tool, but it takes quite some time to learn how it really works.
It's more important to learn editing first.
So my advice is to start simple: tell stories that don't need special effects.
Otherwise you are at risk of spending 2 years on a short, because you try to make an Avatar-prequel or something like that, but you don't have a clue what to do.
About keeping things simple: shoot your first stuff in daylight.
Maybe use a reflectionscreen (or a big white surface) to add light, but avoid needing dozens of lights to lght the scene.
By keeping things simple, you can focus on the storytelling-side instead of logistic and technical hurdles. (You can try that on the next project
To start you need a camera and sound (could be your own mic, but maybe you can find an audioperson who wants to help out on set). A tripod would be nice to get more stable shots.
And don't forget that you need a script.