Hello Seydie !
Here's some tips on jamming :
First, do not stress out ^^ see this as an opportunity to learn, not a competition. Take your time, and it's okay if you can't finish on time, we'll be glad to see your project coming out :)
Second, do not overthink your project, you can add features and polish further after the jam ;) Start simple, add features as you go and get used of your work cycle. Once you get more experience you'll get an instinct of what you have time to do or not.
Third, enjoy the moment ! It's as important as participating, do not overwork yourself and be at your own pace
If you ever need help on anything, we also have a Discord server ^^ we got some amazing members that'll gladly help you on anything, code, art, etc ^^
As jam-stories, one cool thing that happened to me is for my first jam, I randomly invited my brother (who's not specifically into making games) and we worked together. I coded everything and he got the level design in place (we used Godot Engine). We had a blast doing this, we got amazing memories of this. ^^