Very sweet and this is the best kind of age gap romance when it comes to such young characters. That's because it clearly differentiates between adults who are exploiting these younger characters which is wrong from actually loving them and caring about them.
I can't say I fully understand the logic of her acting like a child when even adults wear certain clothes to look more mature or have lucky date items such as shoes for example. Personally, the younger girl came across as relatively mature for her age.
She grew A LOT in 6 months though lol, but the shoes still fit?