You live on a planet that is orbiting a star. There are 200000000000 (twohunderedbillion) stars in the milky way, our galaxy, with an average of 2 planets orbiting them alone. There are an estimated amount of 170 billion galaxies in the observable universe. So do the math, 200billion times 170 billion times 2, and that just gives you the amount of planets which may host life, does not include any moons, which may very well also be suitable for life. So thinking that you are on the one and only planet that has life on it out of that number of possibilities which would crash many small calculators would be a bit ignorant and borderline narcissistic. So yeah there are aliens, don't know if they are already here, will be ever here or were here though.