Basic Aikido Glossary
Usually it is permissible to begin again at 1 after have reached 10, if you are counting in practice.
If, for some reason you must continue, the numbers proceed:
ju-ichi = 11, ju-ni = 12,... ni-ju = 20, ni-ju-ichi = 21,...
All gradings are at the discretion of your Sensei, and simply completing the required daysa does not automatically qualify you to grade.