There are several knowledge areas that you can use as a basis to assess where you are at as a lean-agile coach… and you can also quantify your level (0 to 5; beginner to expert) of know-how per knowledge area.
There is a tool for that: it is the lean-agile coaching competency framework.
The image below shows the framework and the key knowledge areas… and what each are.
Ok … so what now? Go ahead and assess your level of expertise…
then have a retrospective … and make a plan for improvement …with target date of completion; execute on that plan; monitor your progress…then do self assessment again in say six months.