I got my very first eggs about 2 weeks ago, from my Buff Orphingtons. They were 19 1/2 weeks old and I would say a week or two before they laid they would come around our feet and would hunker down and let you pet them. I read last night on this site, that is a sign they are getting close to...
Mine did the same thing at about 18 weeks of age and at 19 1/2 my Buff Orphingtons laid their first eggs on the same day. We have been getting our very first eggs now for the last 2 weeks.