Megan,
I performed on and taught classical guitar throughout college and a few years after that before heading on to seminary studies. Knowing that you already have the discipline of a classical background I would recommend that you find a good teacher (there are a ton of guitar instructors out there, but not a surplus of really good ones) who knows pedagogy, technique, and who will get you started on sight reading and some basic repertoire.
The guitar is a funny instrument, and to play it well requires a skilled and studied approach. If you sit down ten random guitarists of any stripe to evaluate their physical movements, muscle tension, etc, even if some of these are moderately skilled players, I can guarantee you that 8-10 of them will display bad habits that will be holding back their enjoyment and proficiency on the instrument. If, however, you begin with a good teacher, practice your technique, learn to read music and to understand the fretboard, learn a little bit about the repertoire, and become a baseline classical student then everything else will become accessible to you. I can lead family worship, throw in better chord voicings, and not develop major hand cramps in the process exactly because of my classical background.
If you like this instructor, but would still like to learn some good classical basics, I would recommend the following works:
Fredrick Noad's Solo Guitar Playing, books 1 & 2. This will take you through the basics as well as if you had worked through the works by Aaron Schearer, but Noad's works include a lot of good guitar history, better repertoire selections, and a more interesting discussion on technique and the "tricks" of learning to play the fretboard positions. Schearer's works are competent, and have been used by a lot of guitarists, but he was a better instructor in person than he was a writer, and I found his method books to be too dry for my liking.
Charles Duncan's Guitar at Sight. This is a fun and innovative way of learning the to read music on the guitar. It consists of learning the individual strings, individual positions, and then various combinations of these until the whole fretboard is covered. What is interesting about it is that much of the work is done not on the fretboard itself, but in your head! He gets you thinking about the layout of the notes on the fretboard, and you do many of the exercises by visualizing the fretboard in your head, where you hands would be placed, where your fingers would move, etc, all while looking at the notes in the exercise. It is a tremendously well thought out work, and one that I would recommend to every guitarist interested in learning the oddities of sightreading on our instrument.
Scott Tennant's Pumping Nylon (yes, it does indeed have a big, flexed bicep on the cover...). Scott is an amazing guy, and a member of the LA Guitar Quartet, regarding which I would recommend as listening to anyone who loves great music. The repertoire in this work is quite a bit more advanced that what you will find in Noad, but the value for beginners is found in this book's technical exercises. He goes over slurring, shifting, scales, and such in a much more comprehensive manner than even Noad or Schearer, and he does it in a humorous and conversational way, so even though he is a technique monster, he doesn't make the exercises seem very intimidating. He also takes his years of experience as a student and as a performer, and incorporates them into the work with some great discussions on thinking about practice, breathing, and other helpful pointers.
That's probably way more than you were asking to be given, but I wanted to throw it out there for you in the event that you wanted to head a bit more in that direction, but did not have the resources to get there.
very simple music reading for guitar. You also don't kneed to know how to read sheet music to play guitar, many guitar greats NEVER knew how to read music.
