You have stages of toilet seats planned but she may have different ideas. Give her a choice of potties if you have them. My DS liked the adult potty. Dd liked the little potty. They were different and we needed to be flexible. And 22 months is young in my experience. 3 years - a little before for one and a little after for another - was the magic time in my house. Very little resistance because they were ready.
Full time high school teacher and wife! Full time mom to Gabby (9/04) and Anthony (1/08)