Hi Megan!
My situation was the opposite of yours
I started an FTC team last year and ended up joining a local FRC team this year!
Some things to note:
The engineering notebook is everything
Especially for rookie year teams it may seem like a pain to write out and document everything you do but the judges love it! That alone can move you onto the next event (like Chairman's). I highly recommend starting this as soon as your team is formed. Both VEX and FIRST have examples on how to correctly document your meetings and ideas (bound book and computer versions)
Keep the team small
Last year we had 7 kids and it was perfect. 2 programmers, 1 cadder, and 4 builders. Too many people on one robot can get frustrating fast. The parts are small and it's easier to break up the building into sub-assemblies (like FRC) this also makes it easier to switch out components later on
Order parts early
The parts (especially tetrix) get back ordered fast. Get them this summer if possible. We waited till September to order our starter kit last year and did not receive it until October.
Ask other local FTC (and FRC) teams for help
Asking neighboring teams last year helped us a lot. We didn't have any technical mentors and relied solely on forums and the internet to build our robot. Other FTC teams are completely open and willing to help and answer questions.
If you have any questions feel free to PM me!