Hello Veronica! Welcome to the Disney Parks Moms Panel, and thank you for your question. First, yes, you should make
advance reservations for Disney Dining wherever possible. Many table service restaurants at Walt Disney World book up months in advance, and often times they do not even accept walk-ups, or if they do there is a lengthy wait. To avoid disappointment, and having to wait for a long time, go online and check the various restaurants you may be interested in. You can then view menus, and make reservations right there.
Second, depending on the time of day and location you choose to eat, quick service restaurants may or may not have long lines. It has been my experience that dining a little bit before or after standard "lunch" or "dinner" times helps mitigate the lines. Usually though, the Cast Members are pretty efficient at serving many guests in a short amount of time. The exception to this always seems to be at Animal Kingdom where I find the service at quick service restaurants to be slower than elsewhere - you'll want to plan accordingly there.
So don't forget to make those advance reservations for your table service restaurants. You can do this up to 180 days in advance of your arrival by clicking the link I have provided for you above. I hope this is helpful to you, and please let me know if I can assist you further. Have a magical day!
Kristen