Coming of age short story with a boy at a summer place with his parents, implication of time travelers

Question

I know that I read this recently, so there's a decent chance I'll comb through my reading history at the library and eventually pin this one down. It was a short story in a book of them (I don't remember if it was one author or many) that I read in 2016. It was written in either first person or third-person limited with the viewpoint character being a boy coming into adolescence. He has two parents (a mother and a father) but no siblings. His parents regularly meet with a set of friends who are much more well-off than they are — it's a matter of some social embarrassment to them and occasionally an issue because they take on costs they can't afford to keep up.

In the main course of the story, they're at a summer cabin, or a similar location, with a lake. The other parents have kids, I want to say all younger than the protagonist. At least one of them is an overweight girl, because I remember there's a scene where his neck gets wrenched trying to support her in a chicken fight in the lake. His main motivation for being in the lake is not the kids, who he finds somewhat tiresome, but one of the mothers in the group, where he's starting to really notice her large breasts and low-cut suit. At some point he overhears the adults discussing what would happen if there were time travel, and if they would go back in time to try to prevent tragedies.

And that's where the science fiction part comes in. He overhears some oddly familiar-sounding strangers who come to the cabin and talk unintelligibly to the parents and afterwards, the parents are nervous about potential perils. Said peril apparently manifests itself in one of the kids (possibly that overweight girl) nearly drowning because the kids went out to the lake after the parents had forbidden it, and they didn't realize she wasn't with them. Eventually, the boy realizes that he might have been the stranger who talked with his parents, having found a way to go back in time to warn them.

That's all the details I can conjure at the moment. If I can think of more, or if I can place what other stories might have been in the collection, I'll share that. I wanted to say this was one of the stories from Every House is Haunted, but none of the stories match up. The same with Robert Reed's The Cuckoo's Boys, although he matches up better in terms of the sort of stories he writes (speculative sci-fi).

Answer 1

You were close, it is a Robert Reed story called One Last Game.

The heavy girl is Claudia Hawthorne:

Between rounds, Claudia swam up to him. She was turning ten in another month, and her parents had already bought her a pony as a birthday gift. She explained all of this in a breathless rush, floating high in the water because she was fat and because of her big orange life jacket. Then she said, "Let's be partners. Okay?"
She had to be as heavy as Neil. That's why he asked, "If I say yes, what'll you give me?" Not missing a beat, Claudia said, "You can ride my pony."

The ample woman is Mrs. Miller who is one of Neil's opponents in the chicken fight:

But their opponents were Hannah Miller riding high on her mother's strong shoulders. Mrs. Miller was in shallower water, her suit filling with water as she lifted her eight-year-old into the air, those big breasts threatening to spill free. Then she adjusted her straps and started her charge, laughing as she pushed her way through the lake. Neil watched how the water lifted and broke over the pale smooth flesh, and he stared as the breasts dove beneath the surface, bearing down on him. Then something obvious occurred to him, and he grunted to Claudia, "Hold on. Tight!"

And Neil's neck is hurt in the fight:

Another quick feel; that would be perfect. But the fat girl kept fighting him, twisting her legs and hips, and Neil was underwater and sinking fast when a pain attached itself to his badly twisted neck, causing him to scream and drop deeper, shoving at the girl's fat ass in order to free himself, at last.