Has anyone else experienced a sped up metabolism instead of a slowed one with age?

Metabolism and age are not linked. Metabolism is based on body composition. A cell of muscle at ages 18-28-88 all burn the same amount of calories. Same with a fat cell. Difference is change in body composition. MOST PEOPLE become less active as they age, not due to age, but social factors: no more physical education cl when you go to college or work; paying bills means less time for rollerblading, hiking, playing frisbee or hoops and who has time to weight lift... see what happens. We change our behaviors and our bodies adjust.