How long before possible melanoma is seriously dangerous?

i have a mole on my face that changed recently grew out, above the skin and its gotten hard, the color has always been and still is skin tone and its still less than the size of an eraser head, this was right before this Easter, there has since been no more visible growth, and I just made a dermatologist appointment today, but the soonest they could give me is may 31. Anything cancer related always says its best to catch it fast and I'm worried it is melanoma. Will waiting another two weeks be really bad? fyi there is a history of skin cancer in my family, I'm 21, i hardly ever go out in the sun but I have had maybe 3 serious sunburns in my life.