Is it normal to have a friend who does everything you do?

I have a good friend, I'll call her Sandra. She is very shy. The kind of shy that she only has a few friends (including me) and won't stand up for herself. She doesn't really hang out with many people, and she has rich parents who DO buy her in-style clothes and she DOES have good looks, but she refuses to have a life. Whatever I do, she does. I'll say, "What do you want to do?"
"I don't know. Whatever you want"
"How bout we watch Titanic."
" Is that what you want?"
"Yeah. That movie is funny."
"I know" she'll say
"Actually, I was kidding. It's really sad. I cried"
"Yeah, me too."
One day I'll want to draw, she'll want to draw.
I'll wear a red shirt, so will she.
I hate Obama, she hates Obama.
I like Obama, so does she.
She can't get a life...If you know what I mean, and I have friends I have hobbies. but she just follows me, does whatever I do. And Im not happ with the answer that i should be fflattered, because she's not a friend anymore, more like a walking talking shadow that wont go away. Do other people have friends like this? Is this normal?