What would be better for me to do for my future, getting it expunged or a dismissal?

I have a petty theft misdemeanor charge. This is my first run in with the law. I got a lawyer and she was able to make a deal were when I complete my bachelors, they will dismiss the case. However, she told me that I could expunge it within a year and 1/2 if I wanted to. I don't know which is better for the long run. I'm still debating with what career I would like to pursue between being going into science or real estate.