The short answer is: It depends on your definition of a state or a dynasty.

Now, to give you a more profound answer I will try to establish a historical context and then we need to try to define what we mean by "imperial dynasty (in opposition to a regional power)" and "Chinese".

I will ignore the "Xia-Dynasty" (夏王朝）, because the consent among many western sinologists (Vogelsang, Keightley, Shelach and Jaffe) is that it likely was a myth or just a regional power. Therefore it wouldn't qualify to be called an "imperial dynasty". Take this with a grain of salt, though. There are quite a few Chinese and even some western Sinologists who believe the archaeological evidence found at the Erlitou-site (二里头文化遗址) is conclusive enough to warrant claiming a proven existence of the dynasty. There was quite a debate about this and people got quite heated on the matter. Sadly I'm not qualified enough to tell you who is right and only further archaelogical excavation will help solve this conflict.

Now let's move on to discuss the "Shang-Dynasty" (商王朝). Again we have the traditional sources, like Sima Qian's (司马迁） "Historical Record" （史记）, where he clearly states the existence of the Shang and their rulers. We also have quite a substantial amount of "Bone oracle scripts that suggest the existence of a large regional power. At the same time there were other regional powers in Sichuan and along the Yangzi. They didn't leave behing any writing, but they are nevertheless distinct civlized cultures, with remarkable cultural products. But they seem to all be collections of just a few family clans and they did not seem to pocess any interregional surpassing family bonds kind of power. Therefore Vogelsang does not define them as "states" or even "Chinese".

Now let's move on to the Zhou dynasty. Here things start to get interesting. Because unlike whoever you are refering to in your question Vogelsang pinpoints the beginning of "China" during the Zhou-Dynasty （周王朝）. He argues the ritual revolution, a process which takes place around 9000 B.C., is the defining quality of the first "Chinese" empire. "Chinese", because the milestones of this devolopment, like the worshipping of ancestors and the development of interregional and transfamiliar power structures, are the cornerstones of "Chinese culture". These elements are so prevalent that we can observe their continued existence throughout the rise and fall of Chinese empires, marking them as one of the first markers of Chineseness. Which adds to my point why the Shang aren't seen as the first "imperial chinese dynasty". They weren't a transregional power (imperial), they weren't really "chinese", yet and their hierachies didn't transcend family relationships.

So depending on your definition of "imperial dynasty" you can also call the Zhou the first chinese Dynasty. BUT keep in mind that even the Chinese themselves refer to the rulers of the Zhou as "Wang" (王) meaning King, while the Ruler of the Qin (秦朝） is called "Huangdi" (皇帝) meaning emperor. There are two main reasons why the Qin are called the first "imperial dynasty". First of all they were the first power that unified China politically (The Zhou had a system of smaller Kingships they granted in place, so often they didn't even hold control real power over a region). The Qin achieved this via a centralized power structure. The second reason often cited is the invention of a enourmous bureaucratic apparatus to ensure the control over the empire. In many ways this system prevailed in parts until the fall of the Qing-Dynasty （清朝）in 1911.

If you want me to, I can go into more detail about the inner workings of the Qin, but this will require much more time.

References:

Vogelsang, Kai (2012): "Geschichte Chinas", Stuttgart.

Bodde, Derk (1986): The state and empire of Ch'in. In: Denis Twitchett, Michael Loewe und Denis Crispin Twitchett (Hg.): The Cambridge history of China. 221 B.C. - A.D. 220. Cambridge: Cambridge Univ. Press (Cambridge histories online), S. 20–102.