Many languages distinguish between inclusive and exclusive first-person plural pronouns (“we”). (Click or tap here to see more details)
The inclusive “we” specifically includes the addressee (“you and I and possibly others”), while the exclusive “we” specifically excludes the addressee (“he/she/they and I, but not you”). This grammatical distinction is called “clusivity.” While Semitic languages such as Hebrew or most Indo-European languages such as Greek or English do not make that distinction, translators of languages with that distinction have to make a choice every time they encounter “we” or a form thereof (in English: “we,” “our,” or “us”).
For this verse, translators typically select the inclusive form (including Jesus), but it is possible to use the exclusive form. (“It seems best to use the inclusive form….It’s assumed that…the disciples did not [yet] recognize who Jesus was and so would have assumed that he also could have drowned.”)
Source: SIL International Translation Department (1999).
See also inclusive vs. exclusive pronoun (Mark 4:38, Luke 8:24).