On your tax return you just do NOT indicate that you are a dependent.
On your mother's tax return she does not enter you as a dependent.
However, if you are under the age of 19 or age 19 and a full time student under the age of 24 you may be claimed as a dependent if you meet all the requirements under the Qualifying Child rules whether you are claimed as a dependent or not. The law is if you CAN be claimed as dependent then you must indicate on your tax return that you are a dependent.
Do you actually provide over one-half of your own support?
Use this IRS worksheet to determine support - https://apps.irs.gov/app/vita/content/globalmedia/teacher/worksheet_for_determining_support_4012.pdf
To be a Qualifying Child -
1. The child must be your son, daughter, stepchild, foster child, brother, sister, half brother, half sister, stepbrother, stepsister, or a descendant of any of them.
2. The child must be (a) under age 19 at the end of the year, (b) under age 24 at the end of the year and a full-time student or (c) any age and permanently and totally disabled.
3. The child must have lived with you for more than half of the year. Temporary absences while away at college are considered living with you.
4. The child must not have provided more than half of his or her own support for the year.
5. If the child meets the rules to be a qualifying child of more than one person, you must be the person entitled to claim the child as a qualifying child.
6. The child must be a U.S. citizen or U.S., Canada or Mexico resident for some portion of the year.
7. The child must be younger than you unless disabled.
