How I got my first 100 users for my new project

For background, yesterday I launched my new side project, Modern Will. It's a site that lets users create a 100% free Will and other estate planning documents.

About 2 weeks ago, I posted the project in two places on Facebook, asking people to sign up and join our waitlist. One was a group for Dads that I'm part of (parents are one of our target markets), and the other was on my own page. For the post on my page, I asked my friends to a) sign up and b) share the post if they thought any of their friends would be interested. Between the two Facebook posts I got about 90 total signups (70 from the post on my page and 20 from the post in the Dads group).

I also built features into the flow of the app to allow users to invite their spouse and other people named in their Will to join Modern Will. Since launching yesterday this strategy has gotten me ~10 new users. It's not a ton, and I'm still tinkering with the flow of how this invitation strategy should work, but I think it shows some promise in helping as a growth hack if I can get the average user to invite 1 or more additional users.

I'd love feedback on the process and how I can improve it to optimize for growth, or any other ideas you have!