Multiple irregular moles?

I have several irregular moles(asymmetrical, partially raised, different shades of brown on each, jagged edges), one on my arm, one on the inside of my thigh, and another on my face. I was wondering if I should be worried about these being hazardous to my health? I know the a b c d e of skin cancer, but I never heard of more than one spot appearing with cancer. I am sixteen with fair skin and red hair, and they have NOT been there my whole life. I've also not noticed growth with the ones on my arm and leg, but I feel like the one on my face has slightly grown.