Hmm I feel like most founders I know just started companies after college without much experience. While people that want to get experience first seem to never end up starting a company. I think it mostly comes down to risk adversity.
The difference is that if you have this experience when starting a company, it can help you avoid so many stumbling blocks, and you can skip forward to more mature company stages.
While you can't really compare two companies, I think it's interesting that the company I currently work at (incident.io) has only taken a year to go from me joining as the first employee to 40 people + series A + hundreds of customers now.
There's no way we'd have moved so fast if it wasn't a case of replicating what we already knew worked, tweaked for the environment we found ourselves in.
So yes, it doesn't mean you can't be successful as an inexperienced founder, but I do think it makes a difference in terms of execution.
https://hbr.org/2018/07/research-the-average-age-of-a-succes...
I was under the impression that starting a company in general and 'starting a startup' are not exactly the same thing, though I surely might be wrong about this.
Which I guess makes sense, as they've been exposed to certain industries from top to bottom, as well as people with enough funds to actually invest.