That was around 2003-2004. I remember I had a Numerical Analysis class (CS 131 if I recall correctly) and our professor gave us an MP (Machine Problem). He's the type of professor that doesn't force us to use a specific programming language. He would always tell us to use any programming language that we wanted.
The MP was to implement the Conjugate Gradient Method. I used Python for this MP and I remember that my girlfriend/fiancée used PHP. Everyone else used either C, C++ or Java back then. :)
I'm not sure if I ever used Python any earlier than that. All I remember now is that I also started using PHP and MySQL during those days.