Magic Forums

Hi! I'm a 19 years old Italian boy. I've found this site one week ago and I finally decided to register and introduce myself. I've always been interested in magick but this is my first real attempt to learn and cast spells, ritual etc. I've started reading about meditation, grounding, visualization and of course the FAQs of SoM and I've a few questions: browsing the forum I'm wondering about the Role Players...what does this means? (in a magickal way, I know what a role player normally is :D), and if it's impossible to became a vampire/mermaid/angel why those spell are listed? How can I recognise a "good" spell and a "impossible-to-cast" spell?
Thanks in advance :)