The following stackoverflow question asks for how to get the creation date of a job within Jenkins.
I haven't been able to figure out a way to capture the creation date of a Job from jenkins core. I did find that using the jobConfigHistory plugin provides detail on the create operation of a Job which would be possible to scrape, but I would prefer the core expose this information. For some reason, jobConfigHistory usually shows two change operations before the create operation...which is also a little strange.
Please let me know if I've overlooked an easy way to get the date of creation of a Job. Otherwise, maybe someone knows how to extend jenkins to provide this detail in the project_config of the jenkins api? Or even a way to easily get the create date from the jobConfighistory plugin using groovy script? I'm still researching myself.