Project Financial Freedom #1 - The 500 Million calculation

I am starting this documentation of my challenge to become financially independent. I am doing this for myself and everyone else, who is interested in it for whatever reason.
At first, let me explain how it began...
August 2017: I became obsessed to become financially independent within 10 years. It was a random thought in the first place. I've had no knowledge on passive income or a basic theory. I had absolutely no clue at all and didn't know if it was even possible or done before with my - as I thought they are - limited opportunities. It was this fixed idea that stuck in my head for days, weeks and even month. A challenge which I forced myself to accept just because "why not".
It all started during a random discussion about money with a colleague of mine. I calculated the possible gains of the P2P loans, which I was investing in for a few months at that moment. Immediately I was impressed by the power of compunding. I did some calculations and projections and came up with being just shocked about what's possible.
I was about to turn 25. So I calculated the outcome with my current monthly investing budget of 50 Euro, an imaginary interest rate of 30% p.a. over the next 42 years until I would hit retirement at 67, which is the current retirement age in Germany. I came up with a compounded total property of 520,666,084.85€, which is just shy above half a billion... with only 25,200€ invested over that period of time. Regardless of the high amount of 30% annual return, I was calculating with. This made me very interested in becoming a serious investor. And that's the reason why this whole journey began. I got this immediate believe that wealth is not reserved to the lucky or hard working entrepreneurs, but also is accessible to the ordinary people with ordinary jobs and ordinary lifestyles... just peoply like myself. So I can get wealthy.
Here we go!