I will advise that you get to know this girl better, the 'real'
her in the real world. Sometimes people are good at chatting with
others online, not face not face. When it comes to the real
meeting, they may have nothing much in common to talk about or
something along this line. I hope you get what I meant here.
Afterall what you can see on the screen are merely ascii
characters.
When you said you kinda like her, what is it abt her you like
exactly? Her physical appearance or character?
Bid your time, you are not in a rush, are you? How long have you
known this girl?
Finally, I'm kinda puzzled when you mentioned 'me and the
sis cannot make it liaoz btw' are you trying to say you
once tried to go after the sister but failed thus the sis introduce
her sis to you?
Cheer...