How do you know when you have skin cancer?

I mean, i know it as to deal with moles and everything
but, i'm not so sure what the moles are suppose to look like if
you have it...
i asked my aunt who's a nurse to look at this mole i have and she
said oh gee you don't have it!
and got all mad sooo..
i need some help!!!!!

The only way to know for sure is to get a biopsy done and have the biopsy evaluated by a pathologist. Even Drs can not tell for sure just by looking at a skin lesion.

I had two brown skin lesions, one on my arm and one on my back, that were growing slowly. My older and very experienced dermatologist told me not to worry about them because they were harmless solar keratosis. A couple years later I happened to go to a young dermatologist who had an office much closer to my home. He took one look at those same two brown lesions, which by now were rather large, and said those look like basal cell carcinomas and they need to come off. I told him what the other Dr had said but he insisted they needed biopsying. When the pathology report came back the younger Dr was correct. Both lesions were basal cell carcinomas. You just can not tell by looking at photos or getting a visual appraisal.

If she looked at it, and assessed as being normal, what do you need help with?
BTW, moles are not normally cancerous, and they are not usually the first thing you look for in dealing with skin cancers like basal cell carcinoma or melanoma.
Melanoma doesn't start with a mole, it usually starts as a simple skin discoloration.
I suggest you google "pictures of melanoma", if you want to know what to look for....

When the doctor tells you to sit down cause I have some bad news!