I think you should find out what each person wants. The last thing you want to do is throw a party if no one wants one. Some people assume everyone wants a birthday party, but that is just not so.
For your mother, maybe taking her out to dinner or making her a nice dinner would make her happy. For your children, I just simply ask what they would enjoy. They may want to celebrate together depending on their ages and how close they are to each other. If they don't always get along, I would plan something special and separate for each child.