Is it normal for her to stare at me if she is not interested?

I am a lesbian and I work with another lesbian who I often turn to check out as much as I can and most times even while she is serving someone she is staring right at me and happens to be exactly as I look at her and she doesn't make an effort to look away or hide it. I always get nervous stare back and with a smile I look away and it will happen time and time again. Is she just innocently appreciating me or is she hinting?