She just now tells me she has a boyfriend?

I'm sixteen years old, so i was talking to this girl i met on facebook for the first time and was chatting it up and ended up getting her number, soon after she told me to text her. After a hour or so it was pretty late and i think she ended up falling asleep because when i asked her if she wanted to hang out that weekend she never answered and when i told her bye no reply. So the next afternoon i was texting her and it went on pretty good up till like 12 o clock pm when i was tired and thought she was too. I told her "Ill let you sleep :) text you tomorrow cutie." she replied "I'm not tired at all, but if you are then alright. And just so i don't burst your bubble later i have a boyfriend." Now after i heard this i was so confused on why she made me waste my time talking to her for two days clearly flirting with her and then she finally gets the message and tells me she has one which i do believe she does but don't get why now she tells me? So yea i need advice because I'm totally lost. What i did afterwords was text "That sucks :/" she replied "That i have a boyfriend?" and before it went any further i just said " Nvm :) ttyt" and she said "Hmm:) alright, goodnight!" I haven't talked to her since but did send a message tonight saying what are you up to, with no reply but i could clearly see she was on facebook chat so maybe she doesn't have her phone with her. So yup that's my situation one that i have never been into and need advice that would help thanks. :)