I think

I never learned to close a door

(what even is a door?)

walking through my neighbourhood I noticed how people close their doors and built a fence others rang a bell or knocked on 'em (doors, not the people) and after that, some could come in

I watched and wondered how those decisions may be done came back to my lovely home (I spent years decorating it!) and saw my door being a pun

it's made-of-paper wobbly nature screams of nothing but “come in!”

no one ever knocked or rang an asking bell but that's no wonder after all 'cause I forgot to build them in