I am a dependent on my parents return but have made more than $6300 this year.

You have not said how old you were at the end of 2019.  If you were over 23, then your parents cannot claim you.  If you were 24 at the end of 2019 you are too old to be a qualified child and you made too much to be a qualified relative.  Education credits go on your own return.  If you are in grad school you could use the Lifetime Learning Credit instead of AOC.

https://ttlc.intuit.com/questions/3262984-who-is-eligible-for-the-lifetime-learning-credit

But you say "I already filed a return" -- so instead of asking first, you went ahead and filed?  If in fact your parents can claim you then you were supposed to say that you can be claimed on someone else's return.  The rule is you have to say that if you CAN be claimed.  It is not a choice. If you claimed yourself when your parent could have claimed you, then they will not be able to e-file now.  They will have to print, sign and mail their return that claims you, and you will have to amend AFTER your return has been fully processed.

WHO CAN I CLAIM AS A DEPENDENT?

You can claim a child, relative, friend, fiance (etc.) as a dependent on your 2019 taxes as long as they meet the following requirements:

Qualifying child

• They are related to you.

• They cannot be claimed as a dependent by someone else.

• They are a U.S. citizen, resident alien, national, or a Canadian or   Mexican resident.

• They are not filing a joint return with their spouse.

• They are under the age of 19 (or 24 for full-time students).

• No age limit for permanently and totally disabled children

  •      They live with you for more than half the year (exceptions apply).

Qualifying relative

• They don't have to be related to you (despite the name).

• They cannot be claimed as a dependent by someone else.

• They are a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.

• They are not filing a joint return with their spouse.

• They lived with you the entire year.

• They made less than $4200

• You provided more than half of their financial support. More info

When you add someone as a dependent, we'll ask a series of questions to make sure you can claim them.