App almost ready. Should I start marketing?

Excited and nervous at the same time!

Most of you here, must've come across similar feeling. This questions has been asked and answered many times.

I've been working on my app for over 6 months and it really coming out well.

1. Should I wait to market my app before it is on app store to public?
2. How do you validate your idea? (Outside friends and family)

Would like get some honest feedback here...
3) VROOMCHARGE is a marketplace app that connects owners with an idle EV Charger with EV drivers. Self service app that manages: Listing, pricing, scheduling, messaging, payments, payouts.

I guess I've started marketing by posting this question