Yeh obviously a shit test / tease looking to see what your reaction is. Something several 'gurus' advocate and many people will does this naturally anyway (myself included) is to agree and then take it even further.

For example a response could be: "Ah, you've found me out. You're actually the first girl I've spoken to in 3yrs. Mum said I should get out the house more, so I'm trying to make some new friends tonight."