why do i have to turn my key serveral times before my starter engages?

Starter motor is binding is probably will need to be replaced.

AGREE WITH #1.HAVE IT TESTED AND OR POSS LOW BATTERY VOLTAGE

If it is..... The starter motor, you should be able to hear an audible click as key is turned to the start position. This is true with (most) gm vehicles that have starter motor failures. This is of course, providing that the starter solenoid is still kicking the starter gear out. Best way to fully diagnose, would be to use a digital volt/ohm meter. Determine available voltage at the starter motor. Minimum is around 9.6 volts