Retail Fraud / Shoplifting: Shoplifting in Walmart in Texas

My question involves criminal law for the state of: Texas

i got caught shoplifting in walmart a couple days ago and they took me in he back office and i signed a paper and banned me from walmart and they called the police and i got arrested but realeased on the sight i have appear in court within the next 12 days, and they told me that walmart has the right to sue and will send a letter i havent gotten it yet, just wanted to know what will i expect for punishment, this is my first offense and my record is clean never done anything wrong just was being very stupid and i have learned my lesson, and what should i plea cause i know i did it and i signed a paper i just want to know what the least thing that could happened to me and what will probly happen and im 18 years old and was class c misdemeanor it was $26 dollars of merchandise just done know whats going to happen and what i need to do in court just really scared and mad at myself for doing something so stupid, really need help so i know whats coming for me and what will this do to my future?