system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If the government considers you an adult at 18, than why does federal financial aid deem you inelegible for assistance if you're parents make too much money?

I have some friends that have this issue and can't go to school because of it. I would guess it's because they assume the parents will pay for it. However many parents either cant or won't pay, leaving alot of kids screwed over something they can't control.
gpt
While you are an adult at 18, you continue to be considered a "dependent" of your parents until you turn 25. This is because parents typically financially  support their children even after their 18th birthday. You don't hear about many 18 year olds being kicked to the curb by their parents on their birthday, although it does occasionally happen. Similarly, at 18 you can remain on your parents' health and car insurance, and they can claim you on their taxes. Because of this, it is expected that 18-24 year olds will have an easier time being supported and paying for school if their parents make $150,000 instead of $40,000 every year. This results in the student from the family with less money receiving more financial aid than one from a higher paid family.

However, you CAN qualify under an "independent" status where only the student's income is reported and considered when determining financial aid awards. This can be done if the student is homeless, a foster child, an orphan, in a legal guardianship, or has a dependent of his/her own (ex: a 19 year old student has a baby). 

Edit: thanks for the additional info, guys! You can also qualify for independent status if you are in the military, emancipated, or are married. Also, a "dependent" status on the FAFSA is NOT the same as being claimed as a dependent on your parents' taxes.