Re: 6 months = too old?
You can still try. Start by creating or reinforcing awareness. Every time you realize they are going, tell them so. We also included sign language with potty association, and DS starting signing "potty" to us when he needed to go at just 3.5 mos.! I have found maintaining the awareness of when they have to/are going is the single most important thing to EC'ing, and even if the awareness is all you accomplish, it will help tremendously when PL'ing comes along.