Congrats on getting your first customers. Most founders never get that far.
I’d make an effort to get to 20 paid customers first and interview all of them, especially the ones that churn. You don’t want to dump a bunch of ad spend into a leaky ship, so make sure you fix or build any features you beta testers give you feedback on first. Then push some ads.
Why not just start with the landing page and nail the value prop (MVP). Build a beta and get feedback. Then build and launch a V1.