The 18-year-old made his debut for the Hornets last month.
"When I was playing in the Under-17s championship, my agent told me there were a few clubs interested in me and that one of them was from England," he said.
"He left it there because at that point I was preparing for the final so he wanted me to focus on that, but after the championship he asked if I was interested and I said I definitely was because it had always been my dream to play in the Premier League.
"From then on, I was really happy and felt so motivated. There were other clubs interested in me and rumours about some big teams, but Watford was the team that presented me with a plan and because of that I could see it was a serious offer.
"Even though I signed for Watford, I stayed with Fluminense for the time being and went on to score a hat-trick the first time I played in the starting XI, It was a Copa Sudamericana match against Atlético Nacional and that night was a blessed one. It was a night where my dreams came true.
"One of my goals was a bicycle kick and I did it all in front of the home fans. I will always remember that night. The beginning of my career showed me that nothing is impossible; that there are no limits."