Is this girl into me?

I've been friends with this girl since about seventh grade (I'm now a senior in high school). We've been so so friends. Never great friends...I'd say nowhere near the "friend zone." I could be wrong about that though. She had a huge crush on me in seventh, eighth, and I think part of ninth grade, but unfortunately I wasn't interested. I hung out with her earlier in the week with my other friend (guy who has a girlfriend) and the backseat was full so she, without a second though seemingly, sat in my lap the entire car ride. I went to the movies with her yesterday with my guy friend and she was leaning on me in the movies purposely, I think. Then we went back to his house and his girlfriend came over and the four of us were watching a scary movie and she was snuggled up next to me and grabbing me and holding my hand during the scary parts. Then we were even watching funny videos on the internet and she had her head on my shoulder and everything. Is she into me? I don't know if she's just doing all that because she feels comfortable enough with me because I'm her friend, or she's a tease or what. Is it possible for a girl to be THAT big of a tease?