Taking the CAPI test takes less than ten minutes. It will give you a number that is your score.
Check each line and ask yourself: "Do I know how to do this?" Continue until you find three lines in a row to which the answer is "no". Your CAPI score is the last "yes".
If you want to keep track of development over time, you can download the list in its top right corner.
P.S. It's okay to jump ahead a bit at the start.