step off

“I started to step off the curb without looking to my right.”
What is the meaning for ‘step off’ in this sentence?

In this case it means to step from the curb into the road. Generally, to “step off” somewhere means to take one or more paces so as to leave that place, often moving to a physically lower place. For example, “step off the stage”, “step off the ladder”, “step off the plane”.