Search Results: testing if a girl likes me

Me and this girl were through a mutual friend. So we were flirting and having a great time and amidst all this excitement...

There was a moment where she mocked me that "You are my brother, right?"

I said, "Maybe..."

As soon I said that she got sad and said "why would you say that"

I just shrugged and we continued to flirt.

What was that brother comment supposed to mean? Was she testing me in a way or just hinting me to back off?

So I've been talking to this girl for 2 months we always have good convos and she's always replying to my messages (providing the message isn't something one worded or makes it hard for her to reply) and at times if our convo is fading she tries to keep it going. The problem is though at night when she says she's going bed she tells me she'll text me later/tomorrow but never does, although if i text her she's willing to converse with me. I'm just wondering does this still mean she's interested in me or is she testing to see how much i like her?

ps we talk on whatsapp if that helps with anything and we haven't spoken for 2 days now as 2 days ago she told me she was putting her phone on charge as her battery was low and when it was charged she would text me back but she never did