I filed as not dependent, but I am a dependent, and my mom claimed me as a dependent, how do I change my status as a dependent?

Weather you are a dependent or not your FILING status is SINGLE either way ... what changes is the box on the 1040 saying you can be claimed as a dependent ... and this is handled in the MY INFO section of the TT program ...

Did your return reject or did your mom's return reject?  If your return was Accepted as not a dependent you will need to amend it.  If your mother's return rejected because you claimed yourself then she will have to print and mail her return to claim you even if you amend yours.  

You need to wait for your first return to fully process and you get the first refund. Then you can Amend. So it might be a long wait.  How to Amend
https://ttlc.intuit.com/community/amending/help/how-to-amend-change-or-correct-a-return-you-already-filed/00/25588