We had a discussion about this recently in the Parent section of CC. Fairly long thread here: http://talk.collegeconfidential.com/parents-forum/1823527-is-being-a-girl-woman-interested-in-engineering-a-slight-hook-at-all-schools-p1.html
Generally if an engineering school has close to a 50/50 ratio, women are accepted at about twice the rate as men are. However the advantage is probably not quite that high as the pool of women tends to be stronger than the pool of men. So you probably have a slight advantage, but your chances are still at best about 14%.