Hi I Have A Red Circle On My Leg Just

Hi I have a red circle on my leg just under my knee. It is red and when u look closely it's kida whiteish in the middle kinda ashy as if I scratched it which I didn't ,I showed my family some said it could be psoriasis which runs in my family I am 16 and never had it , but others said it could be ringworm which I also had before ?