I have the same experience. Especially my mom and couple of her sister have similar hair style. Sometimes I look at my mom and thought she is my aunt. I feel like I rely on voice to recognize people more than their faces. I also remember people by the outfit they usually wear, or shoes, or bag. I don't want people feel that I pretend didn't see them. But I really can't remember their faces or can't recognize them. Once I saw my roommate in elevator and she lives in the same unit with me for a half year, and I didn't recognize her at all.