Do it when your child is showing signs. If they are telling you they've gone to the toilet. If they're pulling at their nappy. If they like sitting on the potty, then go for it!!
You can do it whenever ☺️
Im about to start and bub is about to be 25 months. I just wanted to do it in the spring/summer to make washing and stuff easier
Lucky you! Mines stares at me in the eyes lol. I would say if you think he’s ready go for it! I will be starting my 18 month old in November when it starts to warm up