An opening impression is assembled from very little and edited for effect, whether or not anyone intended that. What shows quickly is confidence, appearance, and social ease, and none of those predict much about what a person is like over years. The same limitation applied to however you were read on your first day somewhere.

Treat initial reads as provisional and let them be revised without embarrassment. Give people a second and a third sample before you file them. Give yourself one too, since your own opening was just as partial.