What you are seeing is veins, and not nerves. Veins are blood vessels that carry blood back to the heart from the various parts of the body, while nerves are bundles of specialized fibers that carry sensory signals to and from the brain.
In any case, this is most probably nothing to worry about - veins tend to get more prominent as we grow older, and this is a natural, harmless part of the ageing process. This happens partly because our skin gets thinner as we grow old, making the veins that are close to the skin more visible. In addition, when we are young, our veins are not very close to the skin as there is a layer of fat over them. As we grow older, this fat is usually lost; since our veins are now closer to skin that is thinner and more transparent, they are naturally much more visible. The veins in certain parts of the body, such as the forearms, tend to be more visible because they are larger and closer to the surface than other veins. As for the color, veins do tend to appear a bluish green due to a combination of the color of the blood in them and the effect that our tissues have on the light that passes through them. This is entirely normal and there is no need for you to worry.
You might not be entirely happy with the appearance of your arms, but you will get used to it. And if you look around, you will find lots of other people your age and older whose arms look the same. We usually tend to be over critical of own appearances. It is extremely unlikely that the prominence of your veins is a symptom of any disease, especially since you do not seem to have any other health complaints.
answered by G M