Back up against a wall and stretch your arms out to form a T. Have someone measure you from finger tip to finger tip, the divide that measurement by 2.5
That will give you a good place to start on your draw length. If you cheat I would cheat to the short side on draw length. IMHO most people who start Archery try to shoot too long of a draw.
Finding a Good Pro Shop is good advice but it can be hard to do and all proshops are Not Pro
Enjoy!! and Always Have Fun!!
Dan