Hi Rosa,
How exciting! Your daughters are going to absolutely love the
Beach Club Resort. Stormalong Bay, the main pool, is sure to be a huge hit with them. My teen daughter chose to spend an entire day just relaxing by that pool when I took her for her early graduation gift.
Another highlight of the Beach Club is the proximity to Epcot. You can walk over there through the International Gateway or take a leisurely boat ride over to Hollywood Studios.
You mentioned that you want to be near the main lobby and pool, and have reserved garden view. In this case, I would recommend that you request an upper level room, near the main (lobby) elevator. Some rooms at the Beach Club are a considerable distance from the main lobby. From this location, the main staircase to the lobby is an option, rather than waiting for the elevator. You can zip down to the Marketplace in the morning for a quick bite to eat. Many of those rooms have full balcony's, and several garden view rooms overlook the solarium. While requests are never guaranteed, Disney does do their best to honor them based on availability. Just call 407-W-DISNEY and ask them to add a request for upper level, near the main lobby elevator.
Hope this helps and have an incredible vacation with your daughters,
Kaylene