Very good, and very cute.
Tall female x short male romcom stories aren't exactly rare, but the execution is what matters and this was well-executed.
I wouldn't mind a serialization, as long as the meat of the content is on their lives as boyfriend and girlfriend, which is the best part of this oneshot. Couple growth is a beautiful thing to watch, which is what a potential serialization of this could explore.
Too many male-oriented romances focus too much on the pre-dating "will they or won't they" part for stupidly long periods of time, and then end when they finally get together. This oneshot is a very good read because that part was done quickly near the start and the part where they're (secretly) dating is what gets the focus.
If that's what a possible serialization looks like, yes please! More sweet dating shenanigans!