Hi Tina,
Woo Hoo! Planning your first visit is so exciting and your first visit is especially thrilling because you will also be celebrating your son's birthday.
Personally I love visiting in February and if you visit during the "Value" season dates you can book your Resort hotel room at very reasonable rates. Since it sounds like your dates are flexible and you are looking for the most reasonably priced dates to visit I suggest visiting Mousesavers.com and doing a search for the 2016 room rates. This independent website lists the daily room rates (including tax) for every Resort hotel through 2016. Personally if you are looking to minimize costs I suggest booking a room in the Value category of
Disney Resort hotels. By making a reservation for one of the Value category Resort hotels you will experience all of the Magic that a Disney Resort hotel has to offer while keeping within your budget.
Vacationing at the Walt Disney Resort for four nights and five days will be a lovely vacation for you and your son. There is so much to see and do at Walt Disney World that even if your first visit was 2 weeks long you wouldn't be able to experience everything. My advice is to plan the vacation which fits into your life now and simply immerse yourself in the Magic, knowing you will want to visit again (and again and again and again!)
My final tip is to have your son's birthday celebration (as well as your first visit) noted on your Resort hotel reservation and any dining reservations you make. When you check-in to your Disney Resort hotel your son will receive a special "Birthday Button" to wear each day. Then be prepared for the number of birthday greetings he will receive while wearing his button!
Blessings,
Brenda ºOº