I am 46 years old. i know i am not pregnant but yet my stomach looks pregnant. could this be an age thing?

Poor tone/bloating: could be flabby abdominal muscles due to poor tone. It could be due to an ovarian condition too--unlikely though but if there is weight loss or irregular menstrual cycle see a gynecologist.

Swelling may be bad: Retained air in the gut can certainly lead to bloating. However, a "hard" abdomen raises greater concern, such as fluid (ascites) in your abdomen or intestinal blockage. Ascites can be due to significant liver disease, infection, perforation of the gut, trauma to an organ with bleeding, or even cancer. Intestinal blockage, if present, risks rupture, peritonitis. Concerned, then get checked pls.