I enjoyed this film but couldn't help feeling it had slightly ripped off the wonder years. Similar period/suburban setting, similarly thoughtful kid, not to mention the narrator being an older version of the main character.
To me it just felt like an extended episode of something i'd already seen...
No one has the copyright on narrating one's childhood. Furthermore, if one is narrating one's childhood, naturally the story is going to be based on decades ago.
That's one way of looking at it, I guess, but perhaps the similarities you're referring to have more to do with how similar we are as people; especially as we navigate through our formative years and then later recall how those times and the people we encountered during them helped shape who we have become.
Besides, I'm pretty sure the narration style used to tell the story (an older person looking back at his younger self) had been used a time or two prior to the Wonder Years. Maybe the WY was the first time you'd seen or noticed that style or maybe it made a big impact on you because you experienced it during your own formative years. Who knows but something about that series obviously stuck with you.
That's a good thing but keep in mind the WY was almost thirty years ago. Since then generations of kids have been born; have grown and continue to grow up; and some are even adults now. It's quite possible this movie, That's what I am, and others like it will be their version of the WY. Maybe this is the movie they can identify with, relate to, and later use to both remind them of their childhood and compare future movies of a similar genre.