No shame in that - I’m an actual software developer for a job and I’ve lost count of how many game jams I’ve entered but failed to submit anything because I just couldn’t get even the most basic version of my “simple” idea ready in time.
You might want to do some basic programming tutorials. Not spend a huge amount of time on them, you can totally dive into the game dev side pretty early on, but just a super basic introduction to get more familiar with the terminology. The problem you had with the “move_and_slide” is something you might have solved yourself if you knew what the error message was telling you, but if you don’t have that familiarity it’s just a string of scary computer words. Unfortunately I don’t have one to recommend specifically.
For what it’s worth, the idea itself sounds perfect for a beginner doing a first jam. Lots of people go way too ambitious, this is something you can definitely pull off if you get that basic foundation.