How can I get her more interested?

Were REALY good friends. We've only known eachother as friends for a month. At first, we were just close friends then I started to like her(I'm a guy). I told her and she said that she likes me too but her heads fogged up with stress so she's not sure. Shes 15, going to another high school and I'm worried shell like someone else. Now, I can't kiss her or anything on that level, she's very innocent yet would slap me for trying. What can I do that's flirtatious?