Is her age an issue getting S1 visa?

My husband is going to work for an International School in Beijing in August. The school is going to provide the family members the paperwork we need for S1 type. I also would like to take my grandmother with us who is very healthy but 72 years old. Can someone help me answer to my question asp, please? I'm very worried at the moment leaving her alone in my home country if she couldn't get S1 type.
Thank you.