Urban Spaceman, admittedly it's a little hard to answer your question because the first three lines in question are all tell. But it's also a 1st person narrative, so you're going to get a lot of that. And what's telling in 1st person is exposition in 3rd.
On the question of killing the mystery. I'm unsure if there is a mystery set up so far. The first line, "Looking back on it..." puts us into the past, and indicates that what will follow is backstory. So there's the present moment of the story, and at that present moment the POV is thinking back on what led to whatever predicament we haven't seen yet.
That's not exactly a mystery. We simply haven't read far enough into the narrative to see *why* the POV is regaling us with the past of his life. We do get a hint, however: the volume of the television. The implication of the third line is that at some point the POV and his wife were in disagreement about how loud a football game needs to be to be enjoyed. The POV now admits that it was so loud that "it could be heard in space". An exaggeration, of course (but who knows, maybe this is some type of genre fiction), but it does reveal that he's changed his way of thinking. Or at least understands why his wife was complaining.
Again, however, I'm not sure what the mystery of the first lines are. We simply haven't gotten to why this is a story. And that's where my point and yours, Urban Spaceman, probably diverge. I think the *why*(the initial why/the little why or the hook) can be stated in the first line to greater effect. I take it that you prefer to not know a *why* (big or small) right now.
Would it be boring to know the why? I don't think so. Again, not knowing what this story is about, I'll write two first sentences to illustrate my point.
1) Looking back on it, I can see why my wife left me alone with just my dog and a house of white walls.
2) Looking back on it, I can see why my wife killed our twin daughters and left me for dead on the kitchen floor.
What these lines do, in my opinion, that the current opening doesn't, is give us specifics that have strong, unique visuals. They also answer the *why*. Why are we being told this story now? But the greater *why* (why is this story being written/plot arc), and more importantly, the *how* (resolution), have yet to be revealed.
Why did the wife take everything except the dog, leaving the POV alone in an empty house of white walls?
Why did the wife kill their twin daughters and leave the POV for dead?
And then, more importantly, *how* is the POV going to deal with the narrative complication he's been thrown into? That, to me, is the actual story. What change is he going to undergo in 3000 words, or 6000 words? That's where the mystery comes in at. Will his experiences defeat him, or will he rise above them? Will he go on a vendetta against his wife, and any who helped her?
"Looking back at everything, I’ll admit a couple of things right out of the gate. My first mistake was the TV volume. I’m man enough to agree with my wife’s deeply held belief that a college football game can be enjoyed without sharing it with the people on the International Space Station."
As this stands now, it just feels a little plain to me. The present participle of the first line places the next sentences in a when, but the independent clause that follows doesn't offer us anything of consequence. What the POV will admit would be better shown us than told to us. Interaction between him and his wife would do just that, and we would see how her point about the volume gradually dawns upon him.
The second line would also be better written coming out through a present moment: the POV and his wife arguing over the noise. This includes the third line. Seeing the POV come to this realization and expressing it through the exaggeration of the football game being heard in space.
Honestly, all three of these lines can be rewritten into a present moment for great reader engagement.