Thanks for the advice, but I think I'm going to forego this one for now. The whole thing actually started last semester when I saw her and her older, heavier co-worker at a nearby restaurant. They were both in their uniforms and I was eating alone taking a break from studying. While there, a good song was playing in the background and I was bopping my head to the music. She caught me and started smiling. I was a little embarrassed but then something happened. She kept talking to her co-worker and looking at me. Then she started mimicking my head bopping and I gave her a smile. After that, she started talking to her co-worker again in Spanish and her co-worker told me that the girl said I was "bello" (which meant beautiful). I told her co-worker to tell her thank you and that I thought the same. The co-worker did so and ask me if I spoke Spanish. I said "un poco" (which meant a little). Then the co-worker said "Oh." After about 3 minutes, they both took off.
Now a new semester has begun and I ran into her two occasions. One time, she gave a shy smile and stopped to see if I would do anything but I didn't. The other time, she was entering the elevator and kept looking at me as the door was closing.
The whole thing seems innocent but I worry about something going wrong. First of all, there is no conceivable future between us because of the language barrier. Even though I can somewhat carry a conversation, my Spanish still isn't good enough. I don't really care about her being a janitor (my parents were both janitors at one point). But I worry that people may think I'm taking advantage of her and that's where the trouble would start. I know I'm overanalyzing this but I have to. My plan is just to appreciate the attention for now and leave it at that.