With Sportrick you can assign skills to people and specify different levels for your courses.
In order to do so, click on Settings - List Values
Click on Add and type in the name of the skills/level you wish to create (e.g. children, teens, senior... or beginners/experienced)
You can also add sub-skills (e.g. beginner's yoga - pregnancy) by clicking on the corresponding button.
Skills can be assigned to a determined activity as well. In order to do so, click on Edit next to the skills/level you wish to assign to an activity and select the activity from the drop-down menu. Click on Ok to save changes.