Sometimes, people from outside of your experience may come to visit, and conduct various studies. However, you would most likely never be aware of their presence, unless they intentionally desired such.
I can inform you in this way: 253 years from now, there will still exist no valid evidence whatsoever, that any sort of intelligent alien life exists. There has been conducted a very high volume of work in the effort to locate and/or communicate with some type of extra-terrestrial life, with no success. Currently, there are well over 15 thousand discovered 'solar systems' containing extra-terrestrial planets (as of 2266, that I am currently aware of, there may be more or less, the number is approximate). Of the known systems, none of them contain planets considered to be 'life-friendly', as we understand the processes of 'life' at this point. I can, however, think of about five or six planets residing in outside systems that somewhat resemble Earth. But, no signals have been detected from them, and, the position within the galaxy of these systems suggests that no life could exist there, as they are not within a habitable zone, as you call it.
As a result of this knowledge, and these facts, it is highly unlikely that you have been contacted by 'aliens'. As far as we know, no such beings exist, at least not within the detectable regions of our galaxy. They may certainly exist, but they would be required to exist either on the other side of the galaxy in a similar habitable zone as Earth, or, in another galaxy separate from our own. If so, there is most definitely no possibility of detecting them, at least as of 2266. The technology simply does not exist. If, however, an alien culture does exist outside of our galaxy, or, on the other side of our own galaxy, it can be suggested mathematically that such a venture to Earth would be excessively impractical, as to render such not a possibility. Many studies have been conducted concerning the possibility, including not only physical abilities, but also practicalities, as well as possible cultural suppositions. None appear valid by human thought processes. This does not mean it's impossible, just that it's highly unlikely if the alien life form thinks similarly as we do.
