<human>: Provide a brief overview of the text.

I'm 18/F and I have a friend a year younger, we'll call her Rebecca, who seems to follow everything I do. I pick up new friends, she has to be best buddies with all of them. I pick up a sport, suddenly she's interested in it and picks it up. I start a new hobby, she's all up in my face doing the same things I'm doing. I go somewhere and she's got to be there.

Now I don't mind sharing hobbies/friends/etc with friends and I think that's awesome but this particular friend is getting on my nerves. I know she's not genuinely interested in any of the things she's participating in so why bother? I've heard from other friends that she may be jealous or simply doing it out of admiration. There's nothing for her to be jealous about imo so I really don't understand her. Anyone care to explain? What can I do about it?
<bot>: Friend copies everything I do even when she doesn't have a genuine interest in the activities. Why is she doing this and what should I or can I do about it?