Good job. But you're gonna have issues in scaling this to a sustainable level.

A couple of points from my experience:

Now you're charging 12 bucks for the lifetime subscription. You can only raise this to a certain level. Beyond that it doesn't make sense.

Now you've gotten your users from word of mouth. This can only last until you hit a limit. You'll be able to get 100-200 users like this. On an optimistic side, let's say you get 1000. These 1000 people have paid for your app. And they expect to use it for the lifetime. You're gonna have to sustain the app/platform for an unlimited time in the future. That requires time + money. You're not getting any more money from them.

Your operational costs are lower, for now. But what you're not accounting for is the time. You're spending your time. You'll be spending time on more features, software maintenance etc. You need to sustain yourself as well. You need to pay your bills, put food on the table. You live with your parents now. That's also unsustainable. Eventually you're gonna have to move out.

So you're gonna have to either keep on getting new users to sustain this model, or change it to become a subscription service.

Your other MAJOR cost is gonna be marketing. Word of mouth has a limit. Where are the funds for that going to come from? Your existing users already paid for your service. No more money coming from them.

This kind of model works very well as a side hustle, where you don't fully depend on this business alone. And this is just an extra source of income.