Release it NOW with a 30 day trial. Once someone signs up you have 30 days to complete the billing integration. Hopefully you're using Stripe (if you can) chec

Release it NOW with a 30 day trial. Once someone signs up you have 30 days to complete the billing integration. Hopefully you're using Stripe (if you can) check it out if you haven't. Also keep it simple in the beginning just handle the recurring payments, you can do cancellations, refunds manually in the beginning.