Can someone answer these dreadlocks questions for me?

ok so, im a giiiirrrrrl. Almost 18 and i'm thinking about getting dreadlocks... i have long curly hair but its not what ud call a lot of hair, when its super curly it gets all big and fuzzy, but it just LOOKS like that, its not that thick... i have 4 questions: 1) if i get them, would my not that thick hair b a problem? 2) if i consider removing them, will i actually have to shave my head?? 3) do dreadlocks HAVE to start at the scalp? or can they start after a few inches, so IF i remove/cut them, I can save some hair? 4) ur hair obviously keeps growing, but, does the new hair get naturally dreadlocked...? or remain un-locked..? If u can answer me my questions, id reaaallyyy appreciate it : ) please no insults or negative comments, im just looking for answers. advanced thank you's.