Doing a startup wether a bootstrapped or vc funded is one long series of validation excersises mixed with the eventual app crashes and data loss that spice up your life.

Getting any users validates that they find it interesting enough to sign up, then you must validate more by looking at their interactions, if they are using the app you have done one more validation.

My recommendation is that you get one or more mentors who have done one or more startup and also get into a mastermind group, check out https://mastermindjam.com for help on that.