My son is 10 & my daughter is 6 & their favorite Resort is the Beach Club. Here are a few of the reasons why:
first, the pool is amazing! Stormalong Bay is actually shared by the Beach Club & the Yacht Club & it is like a water park in size & fun. With 3 acres of sand bottomed pool that includes a huge slide that my 10 year old did again & again, plus a lazy river that you can leisurely float around this pool delivers. We stayed there this past October & I still hear my kids telling their friends about it.
Second, our entire family loved having a short walk from the Resort over to Epcot. You go directly into Epcot's World Showcase without huge & confusing lines to wade through. There are still ticket counters & turn styles, but it's the crowd factor that you don't deal with here.
Third, the ferry boat that can take you to Disney's Boardwalk, Epcot, or Disney's Hollywood Studios Park!
All of these are benefits to both the Beach Club & Yacht Club really, but the Beach Club is just that much closer to Epcot which is my kid's favorite in all of Disney World.
I hope y'all have a great time on your first trip! Be sure to stop by Guest Services to get a 'First Visit' badge so that you get a little extra special attention from Disney's Cast Members!