Hi Thamy,
Well my first instinct is to tell you to go to Magic Kingdom everyday, it's my favorite can you tell, however given that you are most likely worried about crowds, I would suggest separating the visits by a day or two.
Magic Kingdom offers the largest number of attractions for families to enjoy and typically tends to be the most popular and recognized Disney Park. When planning my Disney vacation I like to use
www.touringplans.com . The site uses a number of factors like past crowds, special events and holidays and Extra Magic Hour schedules to rate the days of the week that are the most crowded at each park and the expected crowd levels with a ten the most crowded and one the least crowded.
In my experience it is best to avoid the park that is featuring Morning Extra Magic Hours, unless you are arriving right at opening and hopping to another park once the crowds increase. Given past history, the least crowded day at Magic Kingdom is usually Tuesday, with Saturday and then Wednesday next. I like to space out our Magic Kingdom days since the park is our favorite. This gives us a chance to look forward to another visit a few days later. Using the crowd calendar information, I often schedule our visits for the Tuesday and Saturday during our trips.
We enjoy this park so much that sometimes we even schedule a late dinner or attend Evening Extra Magic Hours just so we can visit a third time. Hope this helps. Wishing you an incredible visit!