Only one side would be justified, being an ancient civilization (as opposed to a recent-ish tribe that entered written history only after the Roman conquest), and the biggest economy of the world for many millennia...
Heads of states should be treat of equals, no matter if one country has been around for a couple of thousands of years, or only a bit over one thousand. Also whether it is a stagnant declining empire being left in the dust by other countries, or one of those countries leaving everyone else in the dust, sound also not matter.
Well, tell that to the British first...
During the age of empires British foreign policy was swaggering arrogance backed up by gun boat diplomacy.
It's weird been British in 2018, we are now a small damp mostly irrelevant island in the North Atlantic.
It's always been a bit weird being British - get used to it! As to irrelevance, you might like to reflect on the fact that around two billion people across the world watched a recent marriage in this parish.
Yes it is a bit damp here but on the bright side the weather rarely tries to kill you, nor does the land and nor does the flora and fauna. The nearest thing to a volcano is Castle Rock in Edinburgh OK - Dartmoor int al was formed from a pluton but that was some time ago as well. Our earthquakes are on the sad end of the log base seismic scale. The last tsunami (controversial but there was a major flood) might have been near Bristol and S Wales 100s of years ago. We have precisely one poisonous snake - the adder and they are very rare and keep well away and probably wont even kill you anyway (but it will smart a lot). We have a few poisonous plants but again you would have to be pretty stupid. Funnily enough I had to warn a Floridian about our stinging nettles - they laughed. They stopped laughing after brushing past a patch on a run.
Weird: yep. Irrelevent: no more than anyone else. Damp: I prefer "moist".
At best you can say that there were civilizations in the China area. But it wasn’t until ~220BC that the area was any sort of unified civilization (under the Qin dynasty).
While that is a couple of hundred years before Britons were unified under the Romans it still makes the Chinese at that time “a recent-ish tribe that entered history only after the Qin conquest”.
At least as much entering history as you appear to be crediting the British Isles - given that it was well known back to 1600BC for its strong tin economy and trading culture. That’s not even including the massive amount of known, detailed, and extensive historical evidence of civilization back to 4400BC (Stonehenge is ~3300BC, FYI).
Now were these things like post-Roman Britain? No, but neither was pre-Qin “China”, instead being a collection of warring competing civilizations... much like the Celtic states in England.
Long story short: you’ve bought into the mythology of China.
We have excellent arts and artifacts and poetry and philosophy of great sophistication from China centuries before that. Whether that was a single state or different kingdoms is as beside the point, as whether e.g. some British poets are English, others Scottish, etc.
I mean we have records and arts and artifacts in England before it was called that and unified back to the 6th century BC. We have evidence of massive sophisticated construction back to 3300 BC!
But are those "British"? If not then the point about the Qin dynasty is valid. If so then Britain has the same storied history as China (though not the volume of artifacts). It can't be selective standards for each.