Seriously, I doubt it would even take that long. We get used to shit so quickly, and the news cycles have to keep feeding us new things, the only way we’d keep talking about the aliens if they kept doing new and interesting things. I’d be willing to bet a year later there would be some people who straight up forgot about it. “Oh yeah, aliens! Are they gonna, like, visit at some point or just keep exchanging calls with the Whitehouse?”
People will absolutely have a hard shit about it when it happens, but I think that, after so much sci-fi exposure in our culture, humanity (or, most of it) would be able to wrap their heads around the idea of extra-terrestrial aliens. Unfortunately, a lot would probably just see them the same way they see any other “aliens”, and be xenophobic (or exoxenophobic as the case may be) jerks about it.