I love my friend and she likes me but she has a bf D: what do I do?! P.s. we keep kissing XD?

I'm gay and she's bi and we were at gay prom the other night and we started kissing and stuff but right after we stopped kissing she got a text from her bf that was like "I love you" and she didn't say it back she was like "oh i gtg ttyl" or something and idk what to do. Later that night we were walking to the parking lot and i finally got up the courage to tell her I love her. And since then she started calling me more and twice we hung up and I called her back to tell her I love her but she doesn't say it back she just starts laughing and says ok thanks bye. Her bf turned 19 today and he lives in Canada but she's 13 and she lives here in California. HELP IDK WHAT TO DO D:<