I am very interested in building my own PC. I've saved some money for a while and wanted to try and build one. I want to know that is it difficult to build a gaming PC? Is it possible for a 15y/o with no knowledge about hardwares to build one?
So I was messing with computers back when I was 13. My brother was doing the same with me at the age of 9. It is definitely possible.
However, keep in mind that you are working with some very, very expensive stuff (just think of how long it took you to save up for this), and you need to read, read, and read more until you know everything inside and out before you spend one penny. This is especially important with how fast technology moves because if you don't build it immediately, something else faster/better comes along and what you bought and had sitting is now not the best value for your money.
One thing I would recommend is to simply get a hand-me-down computer for free and attempt to take it apart and put it back together again. Even an older lga775 system would be fine for this. While not the same as a new computer, it will teach you all the important concept and get you 'hands on' with hardware that if you make a mistake on won't be an expensive mistake. This is essentially how I learned, except it was on a pretty expensive machine at the time (IBM PS/2 30-286 in 1989). We then built our first monster 486 from the ground up and then our cyrix p166+ after that. I've built a few systems since then but have found better value in picking up older off lease systems for cheap and just upgrading them--like this Dell 3020 SFF I'm using now that I upgraded the ram to 16GB and then upgraded the processor to a 4790k along with the cooling.