It's definitely an Eastern Box Turtle, Terrapene carolina carolina. I'm glad you have this turtle and are willing to research its needs. This little girl is going to need extra care because she will be vulnerable to shell infections until it completely heals. Keep her pen and shell very clean, and make sure she has a good diet and correct lighting. I'll put in a good link to get you started. You'll find several more links at the end of that webpage for you to follow up with more reading material. Good luck with your new pet!