At 2 years 4 months I'd wait. My issue is my dd is 3 years 4 months and doing the same! Refusing to sit on the toilet or potty. Sometimes rewards work, but most of the time they don't. At the start of Jan we had great success with her using the toilet a lot, but for the last 4 or 5 days she's used the toilet successfully once. Today she's wet on the floor 4+ times. She starts 3yo kinder in 3 weeks for 3 6 hour days a week. Starting to feel a little stressed about it after todays disaster.