Can yellow discharge, no odor, be a symptom of a yeast infection?

Probably not yeast: Vaginal yeast infections usually cause little or no discharge; the main symptoms are itching and irritation. Colored vaginal discharge (yellow, etc) suggests other kinds of infection. At your age (19), and if you are sexually active, this probably is an STD such as gonorrhea, chlamydia, or trichomonas. See a doctor ASAP for examination and testing. Good luck!