Skin Lightening Abnormality? 😐

Is it abnormal to get lighter as you age? I feel like my skin has lightened over the years. I used to be a little darker than my sister and now I'm lighter than her. The last time I could remember me being that complexion was in my sophomore year of high school. I'm not into skin lightening or skin bleaching. The products that I've used over the years were Neutrogena oil-free acne wash, Clearasil acne pads, Mary Kay Acne Treatment, Noxzema facial cleanser, Ambi acne products, Ghana African black soap, Shea Moisture African black soap and Cetaphil. I think that's about it. I haven't used them back to back or one after another this has been over the course of 5 years because I've had problems with acne ,but I'm just curious to why my skin is getting lighter. I used to be a toffee mixed with golden brown and now I'm a Golden brown mixed with a cafè brown. Now I don't use anything on my face just water.