I tested positive for celiac disease through a blood test but waiting to get my biopsy done, but liver & spleen are enlarged can it be cancer?

Organomegaly. Celiac disease is not usually associated with enlargement of liver and spleen. While some leukemias/lymphomas might cause this, they are not common in your age group, and might be associated with abnormalities of CBC or other tests. If you have solid anti-gliadin antibody test, then a small bowel biopsy is probably not essential. Fatty liver, cirrhosis, circulatory issues might be worth excluding.