To Wear or Not to Wear?

Being a girl in a male-dominated field makes me very nervous to wear anything flattering to school.  This could be heels (but who would wear heels to school), boots, skirts, shorts, or even dresses.  When I walk into the computer lab for engineers, I often feel like I'm being looked at.  When I walk into other computer labs or classrooms on campus, though, I feel as if it's the norm.

This often comes as a dilemma.  I know many of us girls wear flattering clothing because it's cute, it's fashionable, or we just feel like wear a dress! However, every time I want to wear something along these lines, I think about the perceptions from teachers or other classmates.  I often feel like they would think I'm dressing up to impress either another guy or teacher, whether or not it's my actual intention.  

There are often instances where I will choose not to wear something flattering if I have an appointment with a professor to simply insure that I'm not being a potential flirt. (I'm not talking about when I work in the lab and need to be wearing long pants and tennis shoes for safety reasons.) 

Do other people feel this way? Should I monitor the way I dress to make sure I don't "come off wrong" to male peers or professors? Or am I being too-self conscious?