what are the first impression for juliet from the audience

This all depends on what act and scene you are referring to. We really only first meet her in Act one sc 3. Is that where you mean? 

yes that is what i mean

Juliet is, at first glance, a naive girl who looks to please her parents. She, however, does show some personal responsibility in the fact that she will only check young Paris out at the party, "if looking is to like..." She does not commit to him right away.