Why didn't he flirt with me ( fake account )?

[Shanice]

There's this boy in my school that were starting to talk . We started talking like two weeks ago in message and yes showed me that he likes me etc . So I wanted to test him out by pretending to be another girl on Facebook . I sent him a message trying to talk to him he answered me nicely at first , until he stopped . I was asking him questions and he wrote that he likes a girl in his school . So I kept trying to convince him to like me instead , but he then started saying to stop texting him and to leave him alone etc . He's also a bit younger then me too , I just wonder why he acted like that . He wrote to me as the ( fake girl ) "will you fuck me? J.k stop texting me".