Is walking ten miles a day too much?!

Is walking ten miles a day too much?

I jumped right onto the fitness bandwagon eight weeks ago, I Immediately started walking 5 miles a day. Within one month I was walking ten. I'm a female in my 40's, Height 5 ft 0. Weight 105. I have 15 lbs to go to reach my ideal weight for my small frame, 90 lbs. My daily walk lasts approximately 3 hours. I don't miss a day, unless it rains. I'm also drinking six 20 ounce bottles of water a day. Eating 1500 calories a day, and burning off approximately 1000 calories from the walking. I am writing down everything I eat in a food journal, as well as the nutrients in everything I eat. I've cut out bread completely. But I've only lost 12 lbs in eight weeks, which is a little discouraging, considering all the walking I'm doing. I can't figure out why this time I'm losing this weight so slowly. Am I trying to hard or what?! Or maybe it's because I'm ten years older than I was the last time I did this!? Maybe I should take a day or two off a week from my walking?

I am glad that you are keeping a diary of your food consumptions. You caloric intake may actually bew a bit low for all of the exercise you are getting. Eating too little can cause the body to save everything it eats as it fears starvation (something that we got from our long gone ancestors), however, that doesn't appear to be a problem.
You are consuming a lot of water. As long as you aren't stressing your kidneys, that should be fine.
The body has a gentically predisposed weight that it will want to obtain, which may or may not agree with your "ideal" weight. One should actually determine one's "ideal weight" by how one feels (including energy level, stamina, psychological outlook, emotional levels, etc.) and not by some insurance company's weight chart, which is what most doctors use.
Yes, you may have aged since the last time you took up this training regimen however, it seems that you are doing fine.
Now, to your question of is ten miles a day of walking too much? Are you enjoying the walk? Is it causing pain in your feet, ankles, knees, hips or lower back? Is it putting what was your social life on hold so as to walk? If so, is that ok with you? In other words, if you are comfortable with what you are doing and it is not causing any physical, emotional or mental distress in your life then it is fine.
The idea of taking a day or two off each week should not be a problem. Those days will allow your muscles to recooperate from all of that healthy exercise.
Wear good shoes. Change them about once a month or so. Stretch before and after your walk. Congratulations!
May it all be well with you.

(If you want to try to burn a few more calories, consistently try to walk that ten miles in a shorter period of time. Progressive intesity works!)