First impressions of people hard to shake, especially when they're bad. But, if you give people opportunities to prove themselves, they'll often surprise you. Hopefully, they grow to exceed your expectations, but unfortunately they may also disappoint you. Even the best pretenders eventually show their true colors; it just takes some longer than others.
Give yourself time to learn whose judgment you trust, who gets things done, and who will show up to help you through a rough patch. In both personal and professional settings, these are the relationships that matter most. But, people can't tell you that they have good judgment, that they're reliable, or that they care about you. They have to demonstrate it through action.
If you're willing to be patient, people will give you all the data you need. So, when in doubt, give it time.