14 yo newbie here with a shopping list and some questions :))

[Slither Seeker]

I don't think a 20 long is too big. how much time will the snake be able to to stay in the tank? um, about twice as long as a 10 ;~). In all seriousness I think the exact point you will want to transfer will be a matter of individual judgment. you'll probably find that you are eventually too short on space to have the decor you want plus two hides. as for the hatchling, I'd recommend keeping the tank super simple at first, say two hides, paper towels and a water dish. with any new snake its good to get the basic husbandry down before adding stuff. this will give you a chance to deal with mites or something else while it's easy to clean the environment. think of it like a quarantine phase. I recommend starting simple and gradually making changes going forward.

i thought a 20 gallon would be too big? i was going to get a 20L at first but i read that i should get a 10 haha ^^; if i do get it, how much time will the snake be able to stay in that tank? and should i get more decor to clutter the tank when it's still a hatchling?