To answer this question, we need to ask two other questions: first, was there any support in Germany locally for a breakup of the Empire into the constituent states, and second, was there any support among the allies to press such a break-up?

For the first, we have to conclude a resounding no. While you are correct that the German Empire as a state was relatively young (closer to 50 years old than 40, but still a child compared to most of her neighbors) that was still long enough for most people in the Empire to not remember anything else. More to the point, the idea of a German state was a lot older. If anything, the war helped contribute to an even greater sense of German nationalism. Compare this to Austria-Hungary, were nationalist movements for the various ethnicities in the Empire had been running strong for decades, and where apparatuses of these new states already existed in nascent form. Indeed, the Empire essentially collapsed before any peace was actually signed, and the only thing that said peace decided was the actual borders of said new states rather than their existence. The existence of German nationalism precluded this in Germany for the most part, and indeed, the explicit banning of the joining of Germany and Austria in the peace treaties should be taken as tacit acknowledgement of this.

To the second, the answer is yes. Sort of. More specifically, France was clearly in favour of hobbling Germany as much as possible, and if support was there, would have almost certainly pushed for a more complete break-up of the German state. The United Kingdom, however, stood in the way. Exhausted from years of war, and wary of crippling what had become an important trading partner and economic engine prior to the war, as well as keenly aware that pushing for a complete crippling of the German nation would have likely resulted in renewed hostilities, they were measured in their response. The result was that the Saar was detached from Germany (with France clearly having the eventual goal of annexing the territory to themselves), although it was actually part of the Kingdom of Prussia and thus not an area with a distinct and unified history defined by being a complete princely territorial unit. Unsurprisingly, the Saar consistently agitated to be returned to Germany throughout the 20s, and of course, eventually was.

However, it is important to remember that Germany still lost a lot of territory in the war, almost entirely motivated by weakening it (the Saar was chosen because of the steel and coal it produced, areas detached in Silesia were also very important industrial centres, Danzig was a very important port) rather than strictly speaking areas assigned based on ethnicities. In this manner, Wilson's 'Fourteen Points' were taken as an excuse rather than a true reason for many of the territorial concessions.

/u/Spoonfeedme below touches many of the major points, but it's important to remember most a few things

The German Empire did lose a significant amount of territory after Versaille. All overseas colonies were lost, along with Ostkantone (Eupen-Malmédy) to Belgium, Memel (Klaipėda) to Lithuania, Elsaß-Lothringen (Alsace-Lorraine) to France (as well as losing Saarland), Hultschin (Hlučín) to Czechoslovakia, Nordschleswig (Nordslesvig) to Denmark, and a great deal to Poland, and Danzig (Gdansk) was released as a free city. Those account for 13% of its European territory, and ~10% of its population. This map provided by the United States Holocaust Memorial Museum does a good job showing what exactly was ceded in Europe, as well as gives a little write up, and touches on other reparations here. A popular French idea was to disband Germany at the time, but neither the United States nor Britain supported that, there needed to be a "Germany" in order for Germany to pay reparations, preferably economically strong. Clemenceau did also push for a fully independent Rheinland as a buffer state.

and a quick correction to /u/Spoonfeedme's post, there was some German support for secession, namely in the Bayerische Räterepublik (Bavarian Socialist Republic), which declared independence in 1918, with all the lands in the Kingdom of Bavaria under it (Modern day Bavaria and some of the palatinate), but was put down by the German army and the paramilitary Freikorps. There was also a short lived Rhenish Republic There were also some other secessionist movements in Schleswig, Silesia, and massive ones in Baden, Württemburg and Swabia. Germanz was not, by any means a happily unified nation after World War One.

Sources:

United States Holocaust Memorial Museum

Werner, Paul Die Bayerische Räterepublik. Tatsachen und Kritik

Joss, Manfred. Schwäbisch-Alemannische Demokratie. Vision und Scheitern eines Separatstaats im deutschen Südwesten nach dem Zweiten Weltkrieg.