As an AI language model, I do not have access to any personal information, and thus, I cannot answer your question accurately. However, I can provide you with some general tips on how to find this information:
1. Ask relatives: The easiest way to find out the name of Mom's grandmother would be to ask family members who might know. Ask your parents, grandparents, aunts, uncles, or older cousins who might have known her. They may be able to give you more information about her.
2. Look for documents: Try to find family records that may have the name of Mom's grandmother. Look for old photo albums, family bibles, letters, or even obituaries that may have her name.
3. Check genealogy websites: Online genealogy databases like Ancestry.com may have information about your family history and can help you trace your family tree.
4. Visit graveyards: If you know where Mom's grandmother is buried, you could visit the cemetery and look for her gravestone. It may reveal her name and birth date.
Remember to always ask permission from family members before sharing their personal or private information publicly.