I've been leaerning programming since i'm 10 (now i'm 13).I never tried godot so i don't know how difficult it is to use it. but i'd recommend unity because it's what i've been using and for me it isn't difficult to use. or, if you don't like regular programming, you can use bolt visual programming! and there's a lot of tutorials from brackeys about most things so in case you need em, you have em. i also agree with what blakeb1's suggestion. One thing i got which helps me a lot in game jams is to plan first. planning helps quite a lot so you can know what to make and so you can schedule when you're going to do it. i'm not much of an artist myself but i also agree with pandaman02's suggestion about making your own art (unlike me who always uses simple shapes). I learned a lot from game jams, mostly time management and coding efficiently. as long as you got a playable game up, you're already a winner.