TAMU is fairly competitive. Sophomores that have a good GPA is a strongpoint, which a handfull of sophomores do not have after Freshman year. Sarahsmilehawk is correct when she says that being a sophomore does put you at disadvantage, but having recs as well as a good CV will help.
As far as the dress code, I'm assuming you mean Philanthropy and Sisterhood days.
The dress is what I describe as Summer Casual, nice but not relaxed. No shorts! Sun dresses and pretty sandals are a plus.