Cynthia, you have my full sympathy. No one can really understand what it's like to have decades of repression lifted unless they have experienced it themselves. It really is hell. You've had a dam holding back the waters your whole life, but suddenly it's gone and the waters are coming at you with overwhelming force.
I so totally understand the need to tell someone close to you, and right away. By now, you may have already done so. I'm glad you've located local resources. My strong advice for you would be to find a gender therapist ASAP. Although you may approach that first meeting with trepidation, the relief you will feel at spilling your guts to a sympathetic individual is enormous. I was shaking at my first therapy session, but I walked out a different person.
You may be feeling all kinds of things right now: guilt at how you've lived your life, regret over not doing something earlier, foolishness for the lies you've told yourself over the years, anguish at what this will do to your family, urgency realizing you want action and want it NOW ... the list goes on and on. Please realize that this issue was not created overnight, and it won't be resolved overnight either. That is a good thing, and not a bad thing. You need time to make the right choices.
You may want to tell your wife, but please do so with extreme caution and sensitivity. You may want to explode with everything, a full reveal. Keep in mind that things we consider all and the same, they will view piece by piece. In other words, you may want to tell her how you've felt your whole life, the feelings you've kept hidden, how you want to go on hormones, how you may want to transition, how you feel like a woman, how you feel when you see her doing "womanly" things, etc. To you, this all may be part of a single package, to her, each and every item is a hammer blow to the head. If you do tell your wife, I would suggest starting very gently and parceling information out over time, giving her a chance to digest it. I don't know what kind of relationship you have with your wife, but rushing this can easily derail your marriage. It is possible to come through this with a satisfactory resolution for yourself while still retaining your family and marriage, and maybe even making it stronger.
I think you've come to the right place. This site is full of people who know exactly how you feel. I have been where you are, and I am still there in many respects, even 14+ months later. I have a long way to go, but at this point I don't regret anything I've done over the past year, although I could have made some very, very serious errors, which is why I'm writing this to you now.
Again, I strongly advise you to seek out a therapist. If you need help with advice on how to approach your wife, just speak up, many, many people here have been there and there are right ways to do it and wrong ways to do it.
Take care hun, and have hope. You've already done one of the hardest things, just admitting the truth
Love,
Tana