You need to check that information. if they are in row 6 on an A380 it would be a 2 class frame (3 class starts at row 7) and there is no 6D. Or 6G for that matter.
But if it actually is row 7 (which I guess it probably is), that’s ok but personally I would pick 22D/G as they are (much) more private. Is the 11 month old small enough for a bassinet? My grandson would have been much to big at 11 months and he is not a big fellow.