I got myself a Nintendo and started playing Pokemon Emerald when I was around 7-8, but the first real game I was playing would be Fifa 2002 when I was 4-5.
Pokemon Emerald was probably the first game I could spend hours playing. I first took the Mudkip, but started a new game and I finished every single mission in the game with a level 100 blaziken, lvl 100Raqueazyas (Not sure about spelling lol, the green flying dragon pokemon), a fully evolved zubat (Dont remember the name, but it was lvl 86), Electrode fully evolved at lvl 95+ and various other pokemon that I don't quite remember. Man the first time I beat the Elite Four, such a good memory.
I started playing Warcraft III when I was around 9 years old, finished the campaign for that game and the expansion pack, Frozen Throne. Still playing Warcraft III, such a good game. When I was 11, I got into the Total War series. I had over 100 hours of gameplay in Empire Total War multiplayer.