I have coached FLL for the last two years, and I also coach/mentor an FRC team (the high school robotics competition team also through FIRST).
I have a few suggestions, but also a few questions for you:
What grades are the kids in that will be on your team? How many will you have on the team? (To actually compete and have a chance to go to worlds there can be a maximum of 10 kids on the team)
Does your group already have the Lego Mindstorm kit?
Have you reached out to the regional FIRST coordinator in your area? They typically do rookie coach orientation and training in the early fall.
I had 10 kids on my team both years, ranging from 4th through 8th grade and it was too many kids. The most productive meetings we had were when there were 6 kids there - regardless of which 6 it was. There were also some problems with the difference in maturity between the 4th and 8th graders - although the older kids were tolerant of the younger ones, it was obvious at times that they were ready to scream at them.
My first year, we pretty much ignored the project and core values parts of FLL and the team later regretted that decision when we got to competition and had a pretty successful robot, but we couldn't advance because we had terrible project and core values scores. This past year though, we split up our meetings to be more balanced and we ended up not only getting to the regional championships, but also won an award for our project as well as our robot design!
If you want more details, please pm me, I would be happy to help you out in anyway. FIRST is such an amazing organization it is well worth developing the kids' interest starting at a young age because the stuff they get to do with FIRST as they get older is life changing!
