Humans had just begun their exploration of space, they'd not yet met any other species. The first, early, days of human space travel. A kind and gentle elderly woman, who lived alone on a farm far into the countryside, found a very large, odd-looking, "bird" gathering seed from the open feeder she had and they seemed shaky and unwell. When they collapsed, she hobbled outside, loaded them onto the flat part of her walker, and hobbled back inside. Imagine their shock when the old woman was gently singing to them, giving them sips of water, and their wing was bandaged, and all the grandmother wanted in return was a quiet afternoon talking to a new friend. -- DaniAndShali
The claim of "first" is always a nebulous concept. Just ask the people who add it to the bottom of amusing video hosting sites. The first person to discover a distant land full of "uncivilised" natives never ask the natives about who was the first of them to set foot on that land. Or who might have already been there when they arrived.
Such as it is with the "first" encounter with Humans. The Sol system is a surprising font of one-way wormholes. Approximately five minutes after Humanity realised what was going on with them, they immediately used them for disposing of the unwanted sorts. Sending like groups of people down deep time so they could flourish or perish on their own merits. Some deep time colonies arrived centuries before others who were sent earlier. It's all concerned with FTL, relativity, and Humanity's natural egotism.
There are Human colonies that have been in existence for millennia before Humans first landed on the moon. It's complicated. Add technically-timetravel to anything and it definitely gets complicated. Who got in touch with whom and when is very complicated. History is twisted into a pretzel and many ways of logging it involve notes like (Subjective) and (Relative) years. This one is one of the top ten contenders for the First Contact with Humans.