We probably need more info - like how many days are you planning in the parks? Staying onsite or off? How many and how old are your group members. Have you ever been before?
You will not be able to see everything - but, you probably don't want to see everything. This is a nice long visit you have planned, so you will definitely be able to see and do a lot, but you will probably still leave with a list for your next visit.
My suggestion is to look at the websites and the Unofficial Guide to Disney and read up on all of the things that are available. Then, pick your "must-do's" so that you can be sure you get those done during your trip. WDW is so much more than just rides. If you haven't been there is is hard to imagine. The shows are all awesome, each table service meal is an experience in itself, and the shops are amazing.
So, no, you won't be able to ride all rides, see all shows, eat at every restaurant, shop in every shop, swim in all the pools, visit each waterpark, take advantage of all of the recreation opportunities, and just enjoy soaking in every sight.
However, you are fortunate to have such a nice long trip planned, and you will certainly be able to accomplish a lot during it. Have fun!:wave: