Emo how, like black clothes? Tell them to f*ck themselves. Black's a great color for clothes, and I wear it a lot as well, and have also gotten comments like that. Ignore the stereotypes, be who you are, and don't cut yourself. Don't let stupid people make you question yourself. As for acting emo... are you extremely quiet and keep to yourself? I can suggest trying to be more outgoing. If you are sad or angry all the time, that could be the reason. But like I said, as long as you don't come in with spikes and slit wrists, these people are stupid, and don't let them question yourself. Be who you are, and love it. :))
Does it really matter what their first impression is? As long as you don't look ridiculous, it shouldn't be a problem. Whatever preconceptions they have about you before they know you should be able to be most cleared up within 30 seconds of talking to you.
Ignore what other people say about how you dress. Wear what YOU like, Emo or not. If someone can't get past how you look long enough to actually speak to you, that's their issue. You don't want people like that in your life anyway.
Well, sometimes we come off as a certain type of person when we don't mean to be. This is called being true to ourselves. We don't force who we want to be on ourselves but instead we let it come naturally. I come off as a goody two shoes to most people. Some people I work with told me that. I never mean to come off that way. In fact, if they really knew me then they would find out I am the total opposite! So, don't let it get to you. If you are happy with how you look, dress and act Emo Style or not... then do it girl!