Author: Nakashima Tsubaki
Summary: Kojima Mitsu (aka Honey) is a high school girl, but she is so small that she seems like an elementary schooler! One day while she is changing into a maid uniform for a school event (with not much success…because the uniform is too big for her), she find a little bat blocked by the window and helps it.
After that she keeps thinking of herself and thinks it’s impossible for her to become an adult….when suddenly a awsome guy appear in front of her! He is a vampire and as thanks for have saved his “toy”, he helps turn her into an adult with a kiss! (from mangaupdates)

Volume 1 ch 1
Volume 1 ch 2
Volume 1 ch 3
Volume 1 ch 4