C.D.
DO NOT listen to anyone that says he is too young. Did you know that 18 months was noraml to be potty trained until they invented disposable diapers! If he is telling you then start, but let hime lead. Keep asking and talking about it. Right now is an age where they love to see us happy, so make a huge deal out of it, and reward him. I didnt have my girls trained until they were alomost 3, and I was going crazy, spending 50 dollars a week on diapers (3 in them) and my son is 15 moths and love to sit on the potty and sometimes goes. Just keep him excited and happy and he will get it!