Just go to a beginner class somewhere and see if you like it.
If you're starting out uninjured, chances of injury are pretty low, unless you do tons and tons of yoga and/or constantly ignore pain caused by certain stretches.
Don't worry about the various types until you've done it for awhile. The only exception is "Bikram," which you should likely avoid anyway -- it's a strenuous workout in a hot room, very structured and "un-Yoga like."