[Nifty3929]

OTOH, you've learned an important lesson early: You aren't hired until your first day of work. The job search never stops and never ends, until you're really ready to stop working.

Next time when someone agrees to hire you in the hypothetical future, you will keep looking and interviewing, at least until you have accepted a formal offer from someone.

(I'm assuming here that they didn't give you an actual, formal offer even if they did tell you about a starting date)