One of the things I learned running my first startup was that I really don't enjoy running a business. The mountains of admin work, the never-ending decision making, the constant anxiety of whether or not I made the right call, the pressure to never actually switch off and just work work work , all of the pointless 'networking' with people who're pretending to be interested ... it all adds up to a pretty horrible exp…
Being a founder is certainly not fun. The good parts are there, like earning money, interacting with your team and seeing them grow, the first round, the first sale. But the job is quite painful itself.
Please note that not all startups and founders are / want to be funded with billions of dollars. The true story is that you are going to be overworked and fail 99% of times.