Meteor-San Strike Desu!

Everyone lies when they are young, but the lie Kobayashi Hiro told when he was just six haunts him daily to this day. He claimed that he was abducted by aliens, and, even though it was quickly discovered it was a hoax, thanks to national attention, the town became a hotspot and tourist stop for UFO fanatics.
So when the beautiful Yamada Meteor transfers to Hiro’s school, claiming that she is an alien and Hiro is the only one that can save the planet from destruction, he thinks that the whole thing’s a prank. He quickly learns that she isn’t joking.
Meteor is here to test if humanity is worth saving from the monstrous asteroids headed toward Earth. To prove humanity’s worth to the universe, Hiro must complete the assigned missions, even if they are a little perverted.