I require protective gear to teach you how to skate.  That's because skating is a dangerous sport, and falling is guaranteed for all of us sooner or later.  Even very experienced skaters fall regularly, and pads can make the difference between laughing off some embarrassment, or a more serious injury.  Of course wearing pads is no guarantee that you'll avoid injury, but they help reduce the risk.

You'll need knee pads and wrist guards.  Elbow pads and helmets are optional

One style pointer is to wear kneepads under your trousers for the cool look.  That said, if you fall you'll probably make yourself a brand new pair of skating trousers with holes over your kneepads.  The solution is to wear your kneepads over your trousers to prevent this, at least until you feel more confident or don't mind holes in your clothes.