Ookiku Nattara Kekkon Suru! (2019)

Blurb:
Chitose Oki has a huge crush on his nextdoor neighbor Tomo, but there’s one small problem—his height. Back as kids, when his dream girl said she wouldn’t marry him until he grew up, poor Chitose took that quite literally. These days, it’s not just height—one embarrassing misunderstanding after another keeps them from seeing eye to eye. The truth is, they’re both head over heels for each other, but it’s a tall order to confess your feelings to the one you love.

Source: www.anisearch.com/manga/57597