I don't think it's too young .... It just becomes a habit ... I have a just turned 2 yr old who still picks something up and stuffs it in her mouth .... Automatically....I say all day @ not In Your mouth" .... I th k at home she's allowed to suck on everything .... It's gross..... I have two younger ones (14 months and 17 months ) and I started right away telling them not in your mouth and they rarely put anything in their mouth compared to the two year old .... Good time to start