there's no reason to panic--right?

I haven't been teaching that long, (okay, five years--but I still feel as if I don't really know what I'm doing) and one thing I have panicked over since the first day is meeting with parents. It's not that I don't feel confident that I'm doing my best, and it's not that I feel as if I'm not teaching the standards/educating the young/the like. Instead, I think my feeling of panic stems from two main reasons--
1) I have no idea what, exactly, the parent is going to say. As an example, the meeting I have just set up is for a student who is fairly middle of the road--she does not work her hardest, but she does do her work--from what I gathered from her, her mother is concerned that she is not being "pushed" hard enough. what does that mean? Does she want to see more homework? (something that I'm not a big believer in--I use the 30 minutes of homework I am allowed to give a night to assign them reading) Does she want to see more projects? (We are starting one soon...) Or, like some parents I have seen, does she equate worksheets with achievement and grow suspicious when she see fewer (or none) of them?
2) I rarely see the parents of students I am most concerned about, so when a parent does request a meeting, I am immediately seized with anxiety about what, exactly, said parent may be concerned about--am I not paying enough attention to the student? Did I miss some important sign that they are not learning in my class?
Additionally, the team of teachers I work with (I am "teamed" with two other Humanities teachers, a science teacher, math teacher, and PE teacher) are wonderful and have deservingly glowing reputations. Unfortunately, that puts me, as the "newbie", at the disadvantage of not only explaining "why" I do things a certain way (Writer's Workshop, Literature Circles) but also why I do not do things the same as the other teachers on my team. My reasons for the way I teach are, I think, deeply felt and backed up by research and experience, my reasons for the things I don't do the same--are not quite as comfortable (especially because both of my co-teachers are male and older and play on the "professorial" aspects of their characters--I am small, young, and blonde--I don't have a professorial air quite yet).
I have a meeting scheduled with a parent soon; I am a professional; why does this worry me so much?
edited to add:
I should mention that, most of the time, my anxieties are totally, totally, without reason! Mostly, the parents I have worked with just want the best for their children--and, in 7th grade, it's hard to know what's going on in class if you ask your child and only get "nothing" as a response! Involved parents are great--but, for some reason, this is what I get anxious about!