Was it a bad idea in taking my shirt off when introducing myself to a girl?

Well, today was a really nice day at my college, and I saw this really hot girl on my way to class. I decided to take my shirt off and go talk to her. When I introduced myself she seemed kind of weirded out, so all I could think of doing was bouncing my pecs. Once I did that she just walked away. Was taking my shirt off and doing a pec bounce a bad idea, or is this girl just playing hard to get?