2 years is the recommended age (or at least that's what I was told last time we saw the CHN), and there are special 'first toothpastes' that you can buy at the shops - just have a look and it'll say on the box. You only need to use a tiny smear of it on the brush. I've read that some people have started using toothpaste a little bit earlier but I assume that'd be with a non-fluoridated toothpaste as one of the concerns is that bub will swallow the toothpaste and ingesting too much fluoride isn't a good thing. HTH.