A question like; where Bitcoin started, probably isn't possible to answer. There are two reasons for this, firstly, Bitcoin doesn't exist in a specific place. Secondly, the origins of Bitcoin are a mystery. Bitcoin is a blockchain network that exists all over the globe. The first few computers that ran it were probably in the USA, but this isn't certain.
In 2009, the domain Bitcoin.org came into existence, and in late 2009, a person or group calling themselves Satoshi Nakamoto published the now famous Bitcoin whitepaper. From there more people around the world began operating Bitcoin nodes, which mine Bitcoin, and make the blockchain work.
Although Bitcoin started in 2009, it didn't get much attention globally until 2012. Many people began buying Bitcoin at this time, and Bitcoin exchanges popped up all around the world. At this point Bitcoin nodes were all over the world, so we can say that a few years after it launched, Bitcoin become the first truly global decentralized currency.
We still don't know who is behind the development of Bitcoin, or where the design work was done. Some people think that the person or team was Japanese, due to the name Satoshi Nakamoto. There is little evidence to support any specific theory of Bitcoin's origins, or first node location.