This IRS tool "Whom May I
Claim as a Dependent?" would be a great tool for your mother to determine if she can claim you as a dependent or not. As Hal_Al stated above, "The rule is if you CAN be claimed, not if you ARE claimed." So, if you qualify as your mother's dependent, it would probably be best to allow your mother to claim you and your child.
This is assuming your child passes all other dependent requirements, which can also be verified by using the same linked IRS tool.
https://www.irs.gov/help/ita/whom-may-i-claim-as-a-dependent
