You'll have to file a declaratory order with the TX BON. You need to go thru this process before you start school to make sure they will accept you. Go to their website or call them to learn about the process. You basically obtain court documents to send them and write a letter to them explaining the circumstances of your arrest, how you're life is different, etc.
Very important to do this before going to school. I heard of some one that totally went thru the RN program and when she applied for her license the criminal record showed up and she was never approved to sit for the Nclex. Can you imagine how awful that must be? So do the smart thing and make sure they'll allow you to sit for the nclex. Once you get the paperwork to them, it's about a 6 mo process to hear whether or not you're approved.