I'm new to making games and I use Gdevelop my first game is unplayable my second game is playable I'm participating in the game jam because I cant come up with a game idea and for fun
The above advice I think sums up game jams pretty nicely. Personally I do game development as a hobby with zero ambition to turn it into a profession and that really takes the pressure off, but you will find many people here are truly trying to become developers and so they take their work quite a bit more seriously. Which is great for guys like me because the best way to improve your skills, become inspired and create better things is to surround yourself by people who are much better than you are at it. There is nothing healthier and no better way to improve at something than to compete, and test your skill against other developers, designers and artists, it will raise the bar for you and push you towards improvement.
I'm living proof, 5 years ago I was exactly where you are today and thanks to game Jams I have made 7 fully functioning and fun games. Hell last year I placed 6th in the Interstellar Game Jam 5 and I think I owe all of that to the amazing community and talent within and these game jams for pushing me to do better and better with each game I make. If you want to make better games, you're in the right place!