Balance, by definition, is an even distribution of weight that enables someone (or something) to remain upright and steady. When used to describe a concept, like work/life or home decor balance, it refers to elements that are in the correct proportion. Both textbook definitions are relevant when you're working on improving personal balance - it's about distributing your body weight in the correct proportions, if you will.
There are many factors that go into good (or poor) balance: The transfer of information from your brain to your nerves to your muscles, the position of your center of gravity and how that connects to the spot where your feet touch the floor, and the support your feet have when they're moving you from point A to point B. All of these things can be improved upon, though, regardless of your age or current skill. The key? Being as fit as you can be.