I am about leave a friendship but don't know if I should yet.

I met her in graduate school. We were both new in town, I was from a another state & she was from Canada.

She was very caring, we laughed together and she was protective of me too.

Then she started to imitate me, if I wore a suit to school, she wore a suit the next day.
If I had bought certain foods or beverage in my home that I would offer her, she would copy my grocery list.

I had ideas about how I would my use degree in our field but she wanted to teach and then she suddenly wanted to use her degree the same way I would.

The final straw was when I transferred from that school to a more competitive school in my home state, the first words out of her mouth was, "Yes I am thinking about transferring too, in the same city as me!"

Is this stalking? Is it even worth confronting her or should I just leave the frinedhsip?

Have you ever confronted your friend about any of this? You should be flattered... but at the same time I see how this is getting boardline obsessive on her part. If she doesn't mean that much to you, drop her. If you two really had a good friendship, minus all the "copy cat" going on... you at least should discuss this with her. Maybe you just need to tell her what you see and how you feel about it... and while you're flattered, you really wish she'd be her own person. You became friends with her for her special qualities not because she was JUST LIKE U. Maybe if you take that angle with her she'll understand and change... and if she doesn't then you can leave... but at least you know you tried. It seems like she's so obsessive that if you don't even talk to her... she might just keep calling you or stopping by anyway. Good luck to you!