I think many commenters have pointed out reasons why this model is not suited to widespread user adoption, but I just want to say that may not be a bad thing. Meme content moderation is not a big problem if your users are not the type to submit or upvote a lot of low effort memes in the first place. A paywall will inherently limit your user growth, but if the users you get end up being people who are happy to create and support high quality content, that seems pretty ideal to me (unless you are looking for maximal growth, VC level returns, and/or an IPO).
If there’s a mailing list or other way to get notified when you’re ready to do a full launch, I’d love to sign up for that!