How do I work with this pushy co-worker?

This co-worker makes me extremely uncomfortable, she watches me and looks at what I am doing. She will try to act as my supervisor and I have turned down her requests because she is not my boss? She uses my age as a way to take advantage of me. I am young and do not have much experiences in the work place than her and tries to get me to be her "assistant".

I have swapped my shift so I rarely ever see her but when I see her she acts like how I described above. I am not the only one who gets treated like this, besides the staring.

She is extremely weird, I feel very unsafe and uncomfortable around her. She is also very bipolar in a sense she is friendly one minute and the next I feel like she is going to back stab me. She is always near me or finds ways to be near me, staring and all.

I dont feel this should be brought up to the manager because I feel like it isn't messing with my work too much. I push her to the side for the most part but she is very full on and me and my co-workers hate it.

How do I manage someone like this? she's a pain in the ass.
How do I work with this pushy co-worker?
Post Opinion