What should I do?

She sat next to me in science she talked to me A LOT. She always talks to me a lot normally. She is always asking me for homework in homeroom. She likes to write "hi" on my arm a lot. And she lightly bumps into me on purpose in the hallway. She signed my yearbook with I love her she is so y on a picture of her that she circled. She wrote hi Jeff on a bunch of pages in my yearbook. She drops her pen on purpose in science and makes me pick it up. She also says that I beat you about my grades on my tests/quizzes. Or she says "I hate you" jokingly if I beat her in test/quiz. One day in science she was wearing jeans and I swear she was trying to feel my leg (does that sound wrong to you?) Another day in science we played this game where we had to sit on the desks and throw a ball to other people in the cl. She was wearing a jean skirt and she told me " today was nto a good day to wear a skirt". So based on what I said should I give her a note with I like you and so on. If yes what exactly should I put on it to the last detail? Model one for me.