Working on a niche for musician

Hello, I would like to create an online course for the following niche:

amateur adult musicians who want to get over performance anxiety.

Is this niche too broad? I could narrow it further by saying amateur adult musicians who play a stringed instrument… but I feel that might be limiting.

Also, I was looking over the niche worksheet. How does my idea fit into: wealth, health or relationships? or am I suppose to define a new market such as “performance.” I could sort of see how this fits into health since it is dealing with the mentality of performance anxiety and how to get over it.

Thanks in advance for any thoughts on this!