I (personally) would refrain from giving advice until I’d read the introduction and had seen how you put the quotation to use.
However: one generally uses epigraphs without commenting on them in the essay that follows. The epigraph’s relevance to your essay should be self-evident by the time you’ve presented your thesis.
By the looks of it, you’d like to explain the quotation to initiate a conversation directly with the reader re: death, which means it wouldn’t be an epigraph but a citation in the body of your essay used to support/develop an argument. The line would be an effective way of starting a conversation, but it’s a kind of conversation you’ll want to engage with after you’ve presented your thesis. Er, in my opinion…
Because if your first sentence is the Stevens quotation then that means you’ll have to write several sentences explaining the already complex line, then even more explaining the relevance to DeLillo’s novel, et cetera, and it takes up precious space in the intro paragraph whose only purposes should be a) presenting the general topic of death in White Noise and b) then very quickly sharpening an argument/thesis.
So I guess you could use the quotation in a body paragraph, where you’ll have more room to explain its importance, or you could slip it into the intro without commenting too much on it initially and then returning to it later in a body paragraph, or you could use it as an epigraph and sidestep the need for explanation altogether (but maybe you want/need to explain it, in which case the epigraph’s not really an option), or you could use it in the conclusion to, like, backwardly illuminate the considerations of your essay.
How’d you like White Noise, by the way? I’m a big fan, myself.