Girl says Im trying to hard.. What do I do?

Im sorry this is kind of long. Im a Guy. Me and this girl are 16. We have been best friends for 3 years. Im starting to like her as more than a friend, and we have been flirting a little, but we have always kind of flirted. She has been leading me on for the past 4 days, I hung out with her at her house and I put my arm around her she just snuggled up against me and put her head on me. Then she would give me random hugs in between cles and stuff like that. Then yesterday she blurted out at the lunch table, "Is it okay to date an older guy?", Well later on I asked her why she asked that (we always ask each other about relationships) and she ask me what I thought about it, and I said "Honestly I don't have a good feeling about it, she said "When do you ever have a good feeling ha, and we always joke around so I said "Whenever Im with you"... And she said hahaha, Then she ask me, "Do you like me?" and I said "Yes" and then she said okay I have to go Im at Volleyball practice. She knew that I liked her before. But today she was mad at me all day. I told her the conversation that we had and she said yea we talked about it yesterday and I ask what she said, she said that I was trying to hard and it was getting annoying, so she stayed mad at me the whole day for nothing. I've acted the same way for 3 years and she has said nothing and she was leading me on all week. I still like this girl. How do I not try so hard? Or how do I still stay friends with her without coming off as Im trying to get with her? Or any other suggestions would be great! Best answer will be chosen ASAP!!! Thank You!!