A first impression is a guess wearing a confident face.

What feels like seeing someone is really a very fast guess. Two minutes of information gets turned into a whole personality, and the process is invisible, so the result arrives in your head as an observation rather than as the hunch it actually is. The confidence is a feature of how quickly it happened, not of how much you know.

Try labelling it out loud, even silently, as a guess. Say to yourself that you think they are stuck-up, and that you have known them for four minutes. Holding it that loosely leaves room for the much more interesting thing, which is finding out you were wrong.