I was developing my idea because I saw a need in people and could patent it and then sell it. I look at the US patents and it does not exist, but when looking for the product in other countries I realized that in china they have for sale a very similar product ... can I develop it here in the usa and patent it to sell?
There is no link between patenting and selling. The answers are therefore different for each head of your question.
Can you develop and sell it in the US?
Sure. Patents are territorial, so a patent in one country has no effect on other countries. Thus, for US purposes, a Chinese patent is irrelevant. If there is no US patent (or application), there is no patent-relating reason stopping you.
Can you patent it in the US?
Probably not. Chinese publications are prior art for any patent application in the US (or any other country). The subject matter of your US patent would therefore have to be novel and non-obvious over the Chinese product. This would depend on what differences your product has over the very similar Chinese one. However, if the differences are neglible, your application would likely be refused as being obvious.