Yes you can count this experience in your application. Make sure though it is a level 0, A, B, or C job from the CNP.
Since it is part time, it will only count base on how many hours you have worked. To be considered full-time, it must be 30 hours per week.
If, for example, you have worked 15 hours per week, then you must have worked 2 weeks in order to get 1 week work experience.
If you have worked 10 hours per week, you must work 3 weeks to get 1 week work experience.
The formula is:
Hours worked per week divided per 30 * number of months worked = Number of qualified experience
Also, you can say that since you were a teacher, you actually worked more than the hours you did teaching, because you had also to prepare the homework, exams, etc. These hours can also count.