Ur 12. I need to say respect. If u get anything done u are absolut legend. I am 15 and still feeling kinda young and stupid. Lol. I mean just do something and have fun. And if its too much pressure u can quit. I need to still promise the feeling getting something finished is amazing so aiming that is good idea. But yeah. Just have fun In a way u feel to
also, if you complete the jam and still think its missing some features that you want to add then you can finish making the game. I think Game Jams helps people get an idea so they can get out of being stuck and so the theme can help point you in the right direction. The more Game Jams you do the better understanding you will have for ideas for games.