There should be some visual feedback you can check out. The indicator color will go red when canceling, yellow when a dash in unavailable, and green when the dash can be done. The girl's dress is also purple when you can dash and grey when you cannot. There is also an input buffer for inputs that register within ~0.15s of an available dash. The character also cannot dash immediately after landing, you have a short recovery period first. Hopefully that helps a little!