And would I not just get slaughtered being a newbie ?
Nope, what will happen is, you will meet Yorkie, he will show you the coffee, tea and introduce you around. You will be able to chat to some paintballers, who are normal folk out for fun, join some as a team for the day, and follow their lead. If however, you charge Rambo style at every opportunity, then yes, you may get slaughtered
there will be an element of finding your feet, getting how the game/field works, and of course the people fighting for and against on the day. But off the field you should find most people are just like you and me, and you will have a laugh. I still remember first time nerves, its fairly normal!
Another bit of advise, just because someone has all the gear, doesn't make them pro. Far from it. Its just a guy as good as any beginner, with all the shiney stuff.