Jourdain2, I have seen "the skull beneath the skin" once or twice on different people, including quite regularly on one particular person. That doesn't make me, or you, psychic. It's a feature of a particular skin type, lighting, bone structure ... I don't know. Maybe in some circumstances it indicates that somebody is close to death, but not when I've seen it. More that somebody was quite thin or gaunt, with clear or translucent skin, in the right light. I've never really thought much about it but I know exactly the effect you mean.
So you saw the skull beneath the skin on a particular woman and, soon after, the woman died. That does not make you psychic.
If you had met that woman frequently before, in similar light, you may have seen the effect regularly. Most of the time it would not have been a sign of her impending death. The fact that you only met her once, and saw it that once, and haven't seen it on many if any other people, has led you to believe - wrongly - that it's a sign of death that is only seen by psychics and that you have psychic ability.
Hopefully that's a comfort rather than a disappointment to you, since it means you did not cause her death by failing to tell her what you saw.