That kid is only 10 years old and still in elementary school, while the man had already started working and was around 20 at the time. I can accept a 10-year age gap if both characters are adults, like when the younger one is already in university. But in this story, the relationship starts when the kid is still in school, which makes it uncomfortable for me. The arts is good tho
I like that you have a clear understanding about the situation but what usually keeps getting left out in this comments is that no romantic relationship was formed or was developing from when he was a child. The child can like him he can't do anything about that but it's not like he's entertaining it. It seems to me that things only developed when he got older so I don't see the problem.
I understand your point, and I agree that the adult wasn't actively encouraging the child's feelings. My discomfort isn't about whether a relationship officially started when he was 10. It's more about the context and the foundation of the relationship.
Personally, I find it hard to enjoy romances where one person knew the other as a child while already being an adult. Even if nothing romantic happened back then and they only got together years later, the dynamic still feels uncomfortable to me. That's just my personal boundary.

is this a grooming kinda of story? nahh i’ll drop this