Cute, professional haircut for soon-to-be teacher?

I will graduate college and be a teacher next year, and I am trying to figure out a good way to cut my hair. My current hair situation:

Medium brown shoulder length hair with caramel highlights. I chemically straightened it about a year ago, and it has stayed mostly straight ever since, but some of it has grown out and gets a bit wavy now. It is layered, with the shortest layer about chin length. My face shape is oval/round. I don't think it's quite tall enough to really be oval, but it's slightly taller than it is wide. I am petite, 5'2", 120 pounds, so I feel longer hair makes me look shorter/younger. I am wanting something a bit shorter than I have now, that looks very professional and makes people take me seriously. Be as specific as you can, pictures would be great!