It doesn't necessarily mean that it is thinning out of effacing. During pregnancy your cervix gets long and hard to support the fetus and to make sure the baby does not come out. You cervix will start to soften so that it can dilate and efface. It can be soft for a while though before any other changes happen. It is NOT a sign of labor since you could be dilated/effaced for weeks before labor begins or you could be nothing and start labor tomorrow. Did you have a internal for some reason?
Re: Soft cervix?
I have been only soft since 35 weeks. Still no other progress. Just talk to your doctor about your concerns.