Would You Consider A Woman Who Is Only 25 And Has Already Slept With 13 Men To Be A ?

My brother is currently dating a woman who is 25 and she has told him that he she has been with 12 other men before she met him and that he is now number 13. In my opinion I do think she is a tramp because most 25 year old women have not slept with that many men. I told him he should be careful because he might catch an STD from her.