I applaud you for at least thinking about the potential size of your audience before launching.
One thing I've seen is that forum admins, especially the hobbyist ones, make one fundamental mistake: they begin their community too early. They don't do their research. They dont define their unique competitive advantage before launching. They don't build an audience of a group of followers. They think launching forums is pretty themes and installing plugins, but the real work and the hard work is figuring out your community objectives before you even launch.
Define your path to success before you even begin, and you will be more successful than 90% of other people.
Amazing! You cleared my head. Do you have any tips on how I can start researching or testing the amount of target audience? For example.. How can I know where to get the target audience? I'm from Israel and the truth is that our forums are almost completely off the internet. I just want to open a forum on a certain topic that I like (even though I'm 28 haha) and invest in it time, money and whatever is necessary. When I read and understand what you say, I actually understand that I don't have the most important thing: an audience.. I would love advice and tips please 🙏Also never forget: you need an audience first. Start out with a blog and see how that goes. Give it a month or 6 and see if you start to receive some engagement. Build up some followers. Try it out on Discord or Reddit and see where it takes you. And if you’d really need a forum.
All those subjects you list aren’t the most easy ones to build up. Many competitors have come and go.