My startup failed about 5 years ago now, and I went and got a real job that was fortunately a step up from where I was before a startup. But for about my first year or two on the job, I felt like I was behind everyone who had joined straight out of college and now knew all the ropes much better than I did.
That flipped after about 2 years at the company, though. By then I knew the company's internal systems as well as anyone else, but I also had this great skill base on how to build things from scratch, how to identify problems that needed fixing without anyone telling me, and how to take initiative and plan out a solution. Many of those skills became invaluable later on, as I started tackling harder problems, while my peers often became frustrated because they were 5+ years out of college and the only thing they'd ever known was how to fix bugs and implement features in one server of one company.