Of course it can change, I mean first impressions are when you don't know the person and then you get to know the person and your impression of them may change or it could just stay the same. Personally, I think it's much easier to change your impression of someone because of how they looked rather than how they acted. But both are still possible. People make impressions of people from how they dress and look unfortunately that's just how it is. For example, the other week I was dressed wearing sporty clothes and I met a girl for the first time and then I saw her again later in the week and I was wearinga totally diff style and she was shocked because she told me the first time she saw me she thought I looked like a troublemaker lol and the next time she saw me I looked really polite and nice. lol its funny how people think they know what a person's like just by what they wear.
Oh, definitely you should get second chances concerning dress! We all have days where our clothes are dirty or we're "caught" in our lounging wear...next time, if she sees you looking stylish or whatever, she'll probably forget or laugh off the first impression all together. If not, she's a snob.
Definitely! My first impressions of people change all the time... sometimes for better sometimes for worse. The guy I like for example, did not give me a great first impression.. he first came off as arrogant and I wasn't attracted to him at all because I thought he was too short and I usually go for tall guys. But we recently hung out and had a great time! He was hilarious and sweet and not at all stuck-up like I had thought. Now I actually like him. It just goes to show you that first impressions are not always everything!