I jumped a girl coworkers car at work. She's really hot and later messaged me on facebook "Thank you for jumping my car Steve! <3 <3 <3"

I already know my LTR will eventually find the messages if I don't delete them. She would never know if I did delete them because it's the only conversation wed ever had on FB. We have an open phone policy. Should I care? Should I delete the messages? I sure wouldn't like it if a guy sent her a message like that. what should my reaction be if she does find them if I don't delete them?