Niche and vision

I am a philosophy teacher for children. At first, I did not have a niche. But it is hard to find clients without a niche. I have multiple niches ideas.
I am actually trying one niche to test my market.
While working on my business ideas, I have multiple ideas and dream of my business and how it will include other activities like coaching for children/teenagers and other activities.
I put that on a side for now while trying to find my clients for my niche.
Here’s what I am questioning:
I read that you need to dream big and work toward that big dream. I envision my company with all these activities, but I feel like it is disturbing my niche work and that I should try first to develop my niche and later will see.

Should I focus only on the niche for now? Or should I keep in mind the company as a whole with that as an objective?

Hope it is clear.
Thank you for your answer.