Short hair, Twist n Rip??
Not a mistake at all. Twist and Rip is good for any length hair. With hair that short, though, it'll be some time before you see any real progress. I'd recommend TnR and then if you have some beads, put some them on a few. That will keep those ones sectioned away from the ones without beads. They will knot up a little faster that way.
Get yourself some Dr. Bronners or Dreadlockshampoo.com shampoo. Or you can go with the Baking soda/apple cider vinegar wash. Just keep washing to get your hair nice and ready, by stripping the oils away. Liquid is better for when you are starting out. Once they are mature, you can use a bar.
You might here people recommend a sea salt spray, but not how to use it. Do not EVER leave it on your hair for more than an hour. I spray my hair really well with it about an hour before I wash it. Then rinse it out really well. Then use soap to wash.
You should start a journal/timeline. I'd love to see your progress from short hair to locks to long locks.