I think Alice's point was that if we were all just hanging around the house that day, we would still all have gotten showered and dressed, as would she. The fact that she hadn't yet doesn't mean that she wouldn't have done.
But she did know that the plan wasn't to hang around the house all day... there was a plan to go someplace. Just that the time hadn't been set yet.
Of course she knew that the plan wasn't to hang around the house all day, but I think she was saying that the fact that everyone was having a shower and getting dressed wasn't necessarily indicative of the fact that people would want to leave as soon as possible, because people would have done that anyway.