because this can get complicated, just run your scenario through the IRS dependent tool....I'd run it twice, once for yourself and once playing the role of your mother when answering the questions.
https://www.irs.gov/help/ita/whom-may-i-claim-as-a-dependent
who earns more money - you or your mom? do both of you earn more than $4300 each? (if yes, you can't be her dependent or vise versa)
who is paying more than 50% of the financial support of your daughter? you or your mom?
it could be that your mom files HOH (claiming her grandchild) and you file single...
