Nobody is accusing you of sexual harassment. They said what they said. You are making some woman uncomfortable. Try to first believe what they said instead of getting paranoid. You are an intern and probably don't have a lot experience on professional behavior. You might be trying to get be friendly but that is coming out as creepy. Stop trying to do small talk if the other people don't start small talk with you neve…
Now there are definitely behaviors that I think can easily be labeled as creepy(leering at people, making inappropriate physical contact, asking too many unwanted personal questions, etc) but there are other behaviors that are harder to automatically equate as such. As an example, I tend to be relatively introverted, and extremely private when it comes to discussing my personal life, this is especially true at work or with people I don't know well. As a result, I typically don't engage in small talk at work, and seeing as I rarely ever bring up my personal life, I very rarely ask about others. This isn't to say I'm not cordial, but when at work I prefer to simply focus on getting stuff done.
At one prior job, I worked with an extremely extroverted and talkative group, not gossipy or inappropriate, but simply gregarious. I would obviously join in when directly asked but I was always hesitant to initiate this kind of discussion. I did over a long period of time end up becoming close friends with one of my coworkers, at which point he let me know that when I first started some of my coworkers thought it was somewhat creepy that I never talked much about my private life.
I only relay this situation to point out how difficult it can be to navigate these kinds of interpersonal relationships, particularly in larger groups. One person's reluctance to discuss their weekend plans, which to me was completely benign, can be another person's creepiness. Just to be clear though, I absolutely think there are behaviors that are very unequivocally creepy or unwarranted, I'm not trying to argue that this is always, or even mostly, a matter of personal interpretation.