You can figure length to weight, there isn't a accurate formula for length to age, too many variables. Mass can be calculated, the IGFA formula doesn't work well for bass, it was developed for tuna. Use L x L X G/1200 for bass as a basic formula weight to length formula that is appropriate for bass.
L = length with mouth closed to center of the tail, G= girth around the widest area with the dorsal fin down.
Age is dependant on the water temperature during the yearly cycle, available food, cover and species of bass. For example a bass could live for 10 years and only be 2 or 3 pounds, if the lake or pond was over populated for the food available. The longest living bass recorded was 23 years, a smallmouth bass in Mass, as I recall. The longest living largemouth would be about 18 years. In California the Florida strain bass live about 15 years maximum, 12 years on average. Northern strain up to 17 years, both under ideal conditions.
WRB