Kids do love kids characters. The ones who don't like them are the adults who want to partake in entrainment created for kids are put off that the protagonist are kids. Look at how big YA is and how the main characters are. Typically a writer will make the protagonist about two years older than the target audience.

The whole idea behind Spider Man was teenagers were regulated to the side kick role in other comics, always supervised and watched over by wiser and more powerful adults. They only kept in High School for 4 years but they kept him in his late teens/early twenties for about 40 years, about the same age as the average protagonist in most YA stories.

I thought this Spider Man was the most like the comics I read as a kid and it made me laugh. Movies are meant to be enjoyed not over analyzed to death. Are you sure you actually like this genre? I can't remember the last time you were positive about a movie and you especially seem to dislike movies targeted at teens and kids.