"Did you enter California before 2017?" -- are they asking if I was born in California? "Did you leave California before 2017?" -- what does this question mean?

These are questions that are being asked for the California return.

When you are asked those two questions, they are asking if you moved to California prior to 2017 or did you move to California in 2017. 

You are also being asked if you previously moved out of California.  In other words, have you moved out of California prior to 2017 (multiple periods of residency in California).