9/13 eastern almost full?

[lds0191]

we're booked on 9/17 magic (got great rates last year!). now trying to book some friends and the only thing left are 4-7 catagories. anyone know why this particular date is so booked? rest of september looks ok w/plenty of cabins left. does anyone know if cabins usually open up 60 or less days prior to cruise? also, would like to hear from other cruisers for our dates. we will be cruising with dd4 and my parents. lds0191