People say that first impressions are the last. I beg to differ.
First impressions can often be misleading.
You might judge someone to be friendly, nice, trustworthy, and decent while that person might turn out to be pure evil in the future.
Similarly, someone who might seem an asshole at first can turn out to be one of the best persons you've ever met.
The point that I'm trying to make here is that don't judge a person by their first impression. First impressions are not always an honest one. They can be framed or might be a screw-up out of being nervous.
Get to know a person and then judge. It'll help you in selecting the right people to surround yourself with.
Time tells everything. Give people some time.