Decentralized means that there is no center. Bitcoin is decentralized. By that, I mean that bitcoin doesn't have a center. There is no single individual or group of individuals who control bitcoin. This is one of the greatest difficulties that people new to bitcoin have in understanding.
This leads us onto the next question.
If bitcoin is decentralized, then who controls bitcoin?
The people who own and use bitcoin are the people who control bitcoin. Bitcoin is open-source, which means that the source code is open to modification by anybody. The catch here is that the code modification(s) must be accepted by all of the network nodes in order for the code modification(s) to be effective.
The hodl mindset
The term 'hodl' is derived from the word hold. If you want to have strong hands, stronger hands than anyone else around you, then you need to realize this: the buying power of bitcoin increases over time. So the longer you hold on to your bitcoin, or 'hodl', the more buying power you will have from your bitcoin. It's all about having the saving mentality that is somewhat lost on today's generation Z. I was born in August 1979, so I am halfway between generation X and generation Y. I am half a gen X and half a millennial. So that means that I was taught the value of saving my money at a young age. In other words, I've got strong hands. I am a hodler. I haven't touched my bitcoin since 2017.
Fair value of bitcoin
This is one way of looking at the value of bitcoin. Generally accepted among economists, the world's entire value of investable assets - stocks, bonds, real estate, land, and art is $300 trillion. There are, at present, 18.5 million bitcoin in existence. So if we divide $300 trillion by 18.5 million we get $16.2 million. So the value of one bitcoin, in today's money, is $16.2 million.
However, we can buy one bitcoin in the open market for $48,000. So basically, bitcoin is 337X undervalued today.