Crush/almost gf advice

So there's this girl at school that I've liked for ages and recently we've become really close. We're both bisexual and been treating it like a relationship so far. But there have been a few issues like she almost never texts and idk whether that's my anxiety being paranoid or whether there's something else going on. Also she's had quite a few relationships before me and doesn't seem able to hold onto them (she's my second, my first was bordering on abusive and controlling so I don't have much to go on) so I'm really inexperienced. My friend says she's just using me and idk what to think anymore. What's your opinion?