Hi Travis!  I too am 41 (almost 42)!  I went vegan overnight at 38 years of age and have not looked back.  

If you can get hold of it, there is a great book called "Becoming Vegan: The Complete Guide to Adopting a Plant Based Diet" by Brenda Davis and Vesanto Melina, both R.D.s.  They are very thorough in discussing meeting nutritional needs on a plant based diet, and for specialized populations (obese, underweight, young, elderly, athletic etc).  This book helped me a lot in the beginning.  You can get it used and very cheap through Amazon or check it out at a local library if they have it (or request that they get it).  A lot of vegan cookbooks have sections at the front on building up basic vegan staples and so on.  And there are MANY vegan cookbooks nowadays.  Some staples would be beans (dried or canned), oats, flaxmeal or flaxseed (a coffee grinder will grind the seeds for you), lentils, flours, oils, vinegars (cider, vinegar etc), nuts and seeds (watch for those that are already roasted as some may contain geletin), fresh produce, tofu, tempeh, plant milks such as soy, rice, almond, hemp, oat etc, Earth Balance margerine, coconut oil, pure maple syrup, turbinado sugar, blackstrap molasses (though its a sweetener, it is also an excellent source of iron and calcium), agave, couscous, bulgur wheat (can be used as a substitute for "hamburger" with tacos, sloppy joes, or in spaghetti "meat" sauce with red lentils added as it has a meaty texture and absorbs spices and seasonings well), quinoa, pastas like spaghetti or macaroni.  If you can't find vegan mayonnaise, google homemade vegan mayonnaise online and you will get a ton of variations on how to make it yourself sans egg.  It is amazingly good homemade.  Even soy free with nuts is excellent.  Walmart I believe has tahini, which is a sesame paste used as a base to make your own hummus for sandwiches or to make your own vegan salad dressing.  it is a great source of calcium and omega 3 fat too.

If you go to the Vegan Outreach site, they also have an online starter guide on how to transition to vegan.

For me, I did a LOT of reading of cookbooks, blogs, nutrition books and also ethics books such as Peter Singers "Animal Liberation", Carol Adams "The Sexual Politics of Meat", Phelps "The Dominion of Love" (talks about Christianity and vegetarianism), "Vegan Freak", "Animals as Persons" by Gary Francione (abolitionist approach to veganism) etc.  I wanted to know everything about it, from every angle.  It is so much more than a diet.  But the change in diet is probably the most effective part of being vegan for the animals and the world and your own health.  

I started out by analyzing what I ate and what was already vegan.  I loved oatmeal, fresh fruit, lentils, homemade bread, and  vegetables such as snap peas, carrots, etc.  I was also already eating raw whole nuts and seeds (pumpkin seeds and roasted sunflower are cheaper seeds).  So I started with basing meals on what I was already familiar with and adding as i went.  This site was a huge resource for me due to the enormity of the recipes and so many of them mainstream and not too far out there.  

If you have a Walmart and Kroger, you are good to go.  you don't need a fancy alternative store to find what you need.  Walmart has plant milks and tofu and usually some specialty items like Earth Balance butter or vegan cheeses.  And if you can't find something, ask the store to acquire it.  I couldn't find tempeh anywhere when I went vegan.  I asked my local grocery store, a chain much like Kroger, if they could add it to the shelves.  I simply filled out a form online and was specific about a brand and description (I found this information by googling tempeh online).  I was contacted by management and within a month it was on the shelves.  It still is years later. Most chain grocers and stores will accomodate, and this is a form of vegan advocacy too.  :)  You will help other newcomers by getting vegan foods on the shelves too!   I also did the same with coconut milk based plant yogurts (SoDelicious) and again they are on the shelves because I spoke up and asked for them.  Once in a great while, for vegan supplements I can't find locally, I order them online through the veganessential store or through amazon as it is cheaper that way anyway.  I just order several bottles.  I only take B12, calcium and D but on occasion vegan DHA.  

Also, at the start, do not worry too much about the minute animal derivitives in foods, such as beeswax, food dyes etc as it might overwhelm you.  There are lists of nonvegan food ingredients you can find online and they can be extensive.  Learn about those later when you feel more confident in your lifestyle and have added more foods and so on.  The more whole and fresh you keep your diet, the less you will need to learn and worry about strange chemicals and ingredients in foods, but even fresh produce can be waxed with beetle juice etc.  Thankfully more and more produce is being labeled as containing these items.  And places like Kroger and Walmart have organic sections for some produce and other items.  I follow the dirty dozen organic produce list and buy the rest of my produce nonorganic.

Hope this helps!  Best wishes on your journey!