Well me personally I would say no to the cowboy boots but that's just because I've never really liked them.
What I would do if the third round is pref (i'm assuming) I would do a really pretty brown sandal with it ( a heeled sandal like a kitten heel to a 2" heel)
Not sure if you're asking about open house or third round...
Open house they may be okay, depending on the campus. They'd better be comfortable, though.
If third round is pref (not sure if it is or not), I would say no to the boots. Pref is a more dressy event, and cowboy boots with a dress are not dressy. I realize that I'm not southern, but cowboy boots and a dress just scream casual to me.
Hybrid Mode
