My son is 2.5 and we've been introducing the potty. He will not sit on it he's just a hyper kid in general. He's been late for everything .. like he didn't sit up til 8 months or earn until 18 months. He is normal but just slower than others. So I'm thinking he won't catch on to this until much later. When i try pull ups or underwear he runs away screaming. Is he just not ready for it yet? When should I try again? Thanks