"Former student" messaged me on Scruff

I worked on and off as a substitute teacher for about five years before I got a full time job in March and quit. Because of that, I felt it was time for me to make a wholesome but real Scruff profile to meet like-minded guys who were generally around my age.

Last night, I receive a message from a 19-year-old asking if I remembered him. I had no idea who he was, so I replied "no." He then told me that he had me as a substitute teacher and thought I was attractive. I said it's possible and asked when he graduated. His reply was that he never did (I'm guessing he dropped out) but it was a while ago, and wanted me to hang out. I politely declined (saying I was looking for guys closer to my age, as I'm in my mid-30s,) and that was basically the end of it.

I know I really didn't do anything, and I'm not working as a substitute teacher anymore, but having a former student message me is like my worst nightmare. I guess I was naive enough to believe it wouldn't really happen to me. Please help me not to freak out.