Is it possible for me to change my name when im 18?

my name is suzana and i hate it, no particular reason i just dont like it its very ugly and i got told by my auntie etc that i can change my name legally at a courthouse i want to change it to suzanne but im not sure if they will let me change it to that cuz it isnt that much diffrent to my real name as im taking the a off and i do a nickname either cuz i did that and very few people were calling me suzanne even tho i put that as my fb name so i gave up n put it bk to my real name so is it possible for me to change my name when im 18? but not completely? and no abusive answers please!!