It sounds more like you are color-weak, not color blind.
My son is color weak, too, and can tell red from green, but has problems with shades like pinkish beige and greenish beige, yellow and yellow-green, or dark blue and dark purple.
Most normal vision people assume color blindness is all or nothing. Actually, most people with color vision problems have some degree of color weakness, not full color blindness. This has led to some people getting denied jobs they could do, or even getting fired from jobs they've been successfully doing for years.