It's a balance thing. I usually put my kids on a scooter until they could balance on it without having to put a foot down. Then all they had to do was to remember to pedal. It can be painfully frustrating to learn balance, but anyone can do it if they just work at it a little. On a scooter you can just put your foot down when you lose your balance. They are cheap too.

You might find a tandem to rent and a friend to go, that way you can get a sense of the task. Great goal- learn to ride a bike.

A first bike. I envy you the joy, pleasure, triumph and rush of your experience. ANYONE on this forum will be able to tell you about their first ride, bike etc.