As someone whos mainly done jams,
DONT BE AFRAID TO CUT THINGS OUT THAT U DONT HAVE TIME FOR
most jams allow demos or incomplete stories and will let you post updatesl ater of on!
get your story out, make it functional
u can worry about the cool features (pronoun selection, changing ui, etc) later if youre still super new to renpy
also also also dont be afraid to find other devs on twitter who are in the jam or whove made VNs and ask them for advice or resources! i would have never learned how to add in the font choice for accessilibity if it wasnt for multiple devs trying to send me forum posts about it