Eye exam (eyeglasses only) - $60. Contact Lens eye exam - $90 (includes eyeglass exam) Pupil dilation and visual fields costs extra. The eye exam costs are more likely to vary from store to store as the optometrist is not directly employed by Costco.
Colorado, as many other states, has determined the age of majority to be 18 years of age or older. Individuals are treated as adults at the age of 18, with some exceptions, such as drinking alcoholic beverages (12-47-901), renting cars, and purchasing a hotel room. When an individual reaches the age of majority his or her parents are no longer liable for their child's actions.
I think a person should be considered an adult at age 21. There are many milestones leading up to this moment, like being able to vote or watch an R-rated movie, but 21 is the age where one is truly able to do everything that an older person can also do.