Stay simple until you need it
I hadn't seen that migration page Jay linked. The differences are even smaller than I thought.
Unless:
- you are already fairly fluent with OO theory
- you plan on looking for work as a programmer, so will be learning OO theory
you're not going to see much benefit from getting into it early.
My recommendation is learn the syntax, learn the functions, but only what you need to maintain your site. By the time you know enough to start getting all "enterprisey" you'll want to throw out your early efforts anyway.
