It's most likely that, yes, you will be seated with others. You can have the request to "be seated alone" added to your reservation, if you wish. Be aware not all requests can be honored.
While you are seated with others, DCL does a good job of matching tablemates (adult couple with other adults only; family with young children; family with older children for example). You will also have the same tablemates for the whole cruise, not a different bunch of people every night.