re: good starting point for infosec
Pfleeger & Pfleeger - "Security in Computing". I really love this book. It covers not only basic security, but also basic networking, basic programming fundamentals, OS design/operation, etc. It also goes into detail on a variety of infosec topics. I don't think anyone can go wrong buying/reading it.
I'd start there imho. The book will introduce material that you might be familiar with, material which you've heard of perhaps but don't know that much about, and also material that you are 100% clueless about.
So, read the book- make a list of the topics you didn't fully understand or want to explore more in-depth and then begin collecting those. The reference section at the end of the text lists a ton of good source material.