Is my niche narrowed enough?

I am starting my own business.
1- I would like to know if my niche is narrowed enough?
Niche: parents that have kids between 8 to 12 years that have sleep trouble.
I would like to offer a ‘sleep membership’ with different services inside to kids and their parents. Then, I would like to expand the offer to other services, like ‘work membership’, etc.

2- In terms of business advice, how do you target a niche? Is it harder to target in social media? Will I have a broader audience and then more clients with a large client target? Do you target your audience, more prospecting than posting on social media?

Thank you for your answer.