to OP --
You're stressing out wayyyyy too early.

First of all, take a huge deep breathe and say "this is only a vacation and a vacation is supposed to mean you RELAX".

:
This board has a LOT of info. Just keep reading and then jotting notes (think copy & paste) whenever you see something that catches your eye. Keep a word document just for that info and review it when you're about 6-8 months away from your trip.
The first time we went to disney the first thing I did was make myself an excel spreadsheet (a planner) which listed when all the parks were open, on which day, what entertainment was available that time of year (try googling steve soares site fmi) - the info he has is usually a week out but the entertainment for things like Wishes, fireworks, some shows rarely changes they still occur and on certain days unless you're going during a special event time of year (International Food and Wine Fest or Xmas time for example).
Once you get that spreadsheet started you can adjust it when you're like 6-8months away from your actual trip and then again at a week out when it actually lists what the schedule WILL BE FOR YOU. Other sites like wdwinfo and mouseforless (google discount disney) and you'll also find a lot of info about discounts available, budgeting, etc. These sites like wdwinfo have a wealth of knowledge (restaurant menus etc) and it's not all so compressed like it might be here on this forum. On this forum you probably have to do a search on anything specific you want to know about. If you do your search first and don't find what you're looking for then post about it. You'll get A LOT of FANTASTIC advice.
Make yourself an Itinerary to help you plan that lists your final flight details, dates, phone numbers to call for this or that, your final reservation confirmations, etc. I take this with me every trip so I am prepared. I also had a word document for a daily plan complete with the menus of the restaurants we chose to eat at and made reservations for, another document for the kids to look at for what snack credits are available to them, another list of dining (what places you might be interested in), etc. The best way to start is small and just grow your knowledge. Make a document for those rides you can fastpass. When you're about 1-6 months out then purchase something called ridemax or any of the trip/tour planners. I've used them all. Mike's is good for a first timer visiting!!
Someone also mentioned getting the Disney book (unofficial guide to wdw). I agree and got one for myself. NOW would be the perfect time to get one of those for yourself.

and start THERE.
A disney vacation is like no other vacation you'll ever take. The planning will be well worth it tho in the end.
The very thing you will NOT want to do on your first trip is GO COMMANDO. We did that and let me tell you, BAD IDEA.

Make sure you plan ahead for afternoon naps, swimming, relaxation. THIS IS A MUST. You will NOT see everything on your first trip to Disney unless you're planning to come for 3 weeks straight. We've visited WDW this is our 4th time (4 weeks each) and we still havent seen everything there is to see. Must be why we keep coming back
The planning part of it is really work but when we're there we often throw the plan out the window and that's when we have the MOST fun. LOL
Just take notes!! Use google, use the search options here, talk to other people when you have questions (when you can't find your answers anywhere else)... you'll be OK
Enjoy the ride!!!