I met this girl at college and she asks me out. We went out twice and she comes to the conclusion she wants to be friends with benefits. Thing is recently when I message her, she doesn't respond and I'd have to text her about 3 times to get a reply. What does it mean actually when I'd have to keep texting her to see if she's still up for hooking up? And how long should I give it before I shouldn't text her anymore?