If you think about it.... you might have a similar sized friend or relative that cycles... and can instruct you on their bicycle. A little one-on-one help is always a great way to learn. And could be a fun outing mixed with a coffee or tea.
I wouldn't worry about balance. Bicycles seem to roll along very well all by themselves when given a good push. If you can walk across a room... your balance is good enough to bicycle about town.
Welcome to the forums and to cycling.