I am reading the book: The Weiser Concise Guide to Alchemy
half way through it, and i highly recommend newbies to read this book. I read many rams books and googled so many terms to understand what i was reading (thins like athanors, reverberating flame, calcinations, and aludels etc..) Had i read this book before i´d have understood better and faster what some of the texts in rams were saying, and what modern day tools might be used.
This is indeed a good intro to alchemy and will help you understand older books.
Also read the Real Alchemy book by Bartlett
Reading them will pay off, no matter when you do. If you prefer to delve into older texts and research terms on your own, use wikipedia and google that is fine.. it´s a personal preference .. in my case i chose the later longer path of learning, in my case reading these books now only confirms what i found earlier.