Yo! 

Really all it boils down to is a place to play an organized game against another team. There are rules, settings, etc. that are agreed upon by the majority of players and then you go at it. We just provide a place for it all to happen. 

In addition to team ladders, there are also 1 v 1 ladders. So, maybe as a team you aren't ready, but the 1 v 1 ladders would give you  and some of your members a taste of what is going on. 

Also, you can join a ladder anytime in the season. (A season is usually 3-4 months) You'll just be at a disadvantage with points.