I agree, start out in one gun with what you have on hand.
Your gun is suitable for IDPA CDP and USPSA/IPSC Single Stack.
Middle Tennessee Shooters near Manchester has an IDPA match on the First Sunday Afternoon of each month, and a "mixed match" with some aspects of both IDPA and IPSC on the Third Sunday Afternoon.
I shoot their straight IDPA matches regularly. They are good folks and will help you get started.