Do you know if the participating in those are fairly warmed-up to the context of writing games?
I'm thinking about it as a programmer. I think that if I had written 2-3 games of a certain kind before, I could whip up new games very quickly, especially if reusing snippets/libraries are allowed.
As always, there's a huge spectrum of ability and preparedness of the participants, and if you browse gaming sites, occasionally you'll encounter a jam-created game.
Those are the top 1%. I'd say on the jams I've attended, a third made decent to good games, a third made playable, but flawed stuff, and a third's stuff really didn't come together for whatever reason.
I'm not an experienced or talented jammer, but usually there's all kinds of people here - total greenhorns, devs working outside the games industry, professionals and hobbyist veterans whose day jobs might not have anything to do with a computer.
I know it was kind of a norm in game dev. I was never brave (or talented) enough to compete in a game jam, let alone finish anything like that though :D
My advice would be to give it a try! There are literally no downsides to crashing and burning, if you do decide to show up. And you'll be surprise how quickly you can improve with very little experience under your belt.
I'd recommend trying to attend an in-person event, and try to join a team, or attend with friends.
I think the biggest revelation will be just how much work goes into making a semi-polished game, and how many different skills are required.
