My very first 'ouchy' contraction with DS was at 6am the day before I delivered him. Up to that point, I had only had BH contractions and they didn't hurt. My belly would be hard and tight but no pain whatsoever. 19 hours after my first contraction, DS was born.
Almost the exact same thing happened with DD. BH, belly tighening, but not painful contractions for months before. Then 6:30am day before delivery, first 'ouch' contraction. 19 hours later, DD was born. So early labor for me is just BH. For my sister though, she labors for up to 3 weeks before active labor actually starts.