Bought blue agave sweetener. Says it's low glycemic. Switched from splenda. Don't like stevia. Am I doing myself any favors? No diabetes, but hi risk.

Low GI foods. Agave and stevia are 2 low glycemic foods, but they still have to be used in moderation. Eat less, eat low glycemic, lose weight and exercise to prevent diabetes. If you are struggling work with a nutritionist/dietician on low glycemic foods.
Maybe . . . Agave sweetener or syrup is comprised of varying fractions of fructose & glucose depending upon manufacturer, thus the glycemic index will vary, but in general, should be less than table sugar. It is considered 40-60% sweeter than sugar so if you use 40-60% less, you might ingest fewer calories. Instead, you should focus on a mediterranean (-type) diet to minimize your diabetes risk. And exercise!