I don't know what I should do to get into environmental engineering.

I'm a sophomore in high school and I feel passionate about becoming an environmental engineer. I've already picked my classes for my junior year and I feel like I'm too behind because of my math level (geometry) and it so happens to be that I find science interesting even though I don't excel in it. I choose two science classes such as research chemistry and AP environmental science and the sequential elective of engineering, and algebra 2. I'm currently in an engineering class that my school provides as an elective and I'm one of the few girls in there and they seem to know more than I do, which makes me feel inferior to everyone. I want to do things that'll help me reach my goal of becoming an environmental engineer. What do I do?