My mother died of stomach cancer at age 34. Is there a genetic test I can take to see if I will get it and likelihood of early death etc?

No routine test. It is possible but it is rare to have hereditary Stomach cancer. So it is unlikely that you have much risk for it. If you want to pursue it further, you should see a Gastroenterologist who can counsel you and may even find a genetic counselor to guide you further. An upper Endoscopy(EGD) can be done easily to look inside your stomach and also do a biopsy for H.Pylori infection which can cause Canc.
See below. Hereditary diffuse stomach cancer has a genetic bases involving the gene CDH1. Some cancer centers can test for this. Please consult the site below for information on stomach cancer and the second site for centers that provide such service.