What did I do wrongg?

[azzurri]

I asked this girl of my job to be my friend on FB and she acceded. We were chatting and she told me that she was at home ( it was 9:30PM) and so I asked her “Can I go to see you?” she said no. Then I said "nice chatting to you,bye." A minute later she had disconnected me from her FB friends. What did I do wrong?
Additional details:
1) after she agreed to be my FB friend she told me that she did not know me. Actually we have never been introduced formally. But I asked her on FB, not personally because I did not dare.
2) We were chatting about us, what do we like to do and stuff. But I noticed that after a few minutes her answers became slower. She was taking more than a minute in answering my questions. Maybe she was bored.
3) She asked me for a photo, but I denied, because,as I told her, I am too ugly.