She teases me in chat...does she likes me?

I met a girl on facebook a month before..i liked to talk to her and she was very friendly to me...we lost contact for some days as my exams were there and we didn't have chat for about 12 days...noyadays I am talking to her as my exams are over but, she was behaving very differently..she started teasing me of things(like do I have any crush on any other girl in the uni).when i said yes and the girl was my senior, she told I was an oldie and liked older girls...and she teased me other things also....she has never been like this...I want to know why has she become like this!! does she like me