I went out onto the lake this weekend with my stepsister (E) and a group of friends. We hooked up with some of E's friends who were having a bachalor party. There was a guy there who she explained was mentally challenged and had a huge crush on her since college. I was a little drunk and at the time I took it as "ok, he's a creep and she wants some space from him." However, when I tried to give her some space she said "No, he's ok."

Upon analyzing this situation, was this just her trying to say "Look at me, I'm valuable" (which how is a mentally challenged guy showing that she has value? lqtm) or was I right in being protective? Just want help analyzing this.