Not all hair dreads, not all hair dreads equally. But conversely, all hair dreads differently.
I say not all hair dreads because there has been a member about a year ago that waited a whole year and nothing really happened. But that's not really a horror story - she just needed a started method so TnR'd and a year later she had beautiful dreads.
Technically, all hair dreads naturally. A very small percentage of people with soft hair just need very long length. That's the biggest factor - length, with hair texture as an obvious second.
Case in point: I had two periods when I was growing out my hair a couple years ago, where my hair didn't do a damn thing. Suddenly I hit a magic number of 7 inches, and it started tangling even with regular shampoo, when ordinarily it would be tangle free. But I backcombed & tnr'd it and cut it off a week later from a nervous breakdown... Thus I grew it out again and at 6-7 inches of hair I began the journey again. The areas with shorter length are, *gasp*, not surprisingly having a hard time. The areas with longer length are maturing very quickly. Guess it's a waiting game =) at least I'm that much closer to mature dreads... I'm almost at 2 months, and had grown my hair out for 10 months as of October... I'd say just keep waiting and when it gets tangly you're good to go. By 7 inches it should definitely be tangling easy, and with some people the magic number is 5, some 6, some even 8.
Good luck! It will happen eventually, trust me.