I'm sure it's ok and the fact the availability calendar is not yet updated could be for a multitude of reasons. I have taken quite a few bookings whilst we have been here in Florida for my villas but do not have access to update my availability calendars as I only have access to that from home in the UK (to prevent people trying to hack my site).

It could also be that the owners are out of town for a few days or a host of other reasons.

As others say, try to contact the owners over the next few days and see what happens.