My thoughts are that you can have two completely different vacations: one of frustration and being overwhelmed by the enormous amounts of people (not researching and planning), or one of magic and joy (study this forum and others, and plan, plan and re-plan). I was at WDW as a child in '74, a teen in '83 and '86, as a high 20 something in '99. Since then, as a parent, we have had trips every 2 years since 2007. The strategy and methods of planning have changed significantly for every trip since '99. Fastpass, crowd levels, sheer size of the resort, number of attractions, dining choices and the must for reservations, etc. WILL be overwhelming if you don't research. The amount of times you are waiting in incredibly long lines and being turned away from restaurants will dampen your spirit and morale. 2-3 hour lines are not uncommon on certain attractions, and full restaurants when you are worn out and famished will only add to your level of dissatisfaction.
On the flip-side, with the right research, you will have a WONDERFUL experience. You can do Disney at a wonderful pace, see most of everything in a 5 or 6 day trip, eat where and when you want, and learn how to never wait more than 20-25 minutes MAX for any attraction in the park - all while having time to relax, swim, change clothes, get ready for dinner ressies, etc. at your hotel in the early and mid-afternoon. Knowledge and planning are the key! You will not regret "being in the know" when you see the look on the faces of those in the park around you that did not pre-plan. As a "Disneyholic", I can tell you that you are in the right place - you have taken the first step toward an enjoyable vacation.
Much to learn, you have!