Why does my star sign fit me to a tee?

I am a Gemini and every description of Gemini I can find is 100% accurate about me. Why is this? I acted like a Gemini before I was even old enough to know what Gemini was. Also my name is Allison and I looked up 'Allison' in Urban Dictionary and it said 'Girls named Allison are so gorgeous the sun could not rise if they did not exist. Men from all over gather just so they can witness an Allison. Not only are girls named Allison beautiful, but they are fiesty, charismatic and truly one of a kind. They will give you the shirt off their back, but do not dare cross them because they can and will be your worst enemy.' among other definitions. Not to be conceited but that pretty much describes me although I don't think I'm very pretty but everyone tells me I am and other definitions said that Allisons dont know how beautiful they are. Why does this describe me also?