What to do when friendzoned?

I Just got friendzoned by this girl I had been trying to get with for 3 months. When I asked her if she wanted to do somthing this summer she sent me an a BIG red heart. I didnt understand what she meant cuz she is the first person I have been trying to get with. She said she would like to do somthing together as friends, and that she was not intrested in trying to get a bf. I like this girl a lot. What should I do to try to make her want me. Should I Just say I dont want to be friends or should I do somthing Else?