When I was a child, I lived across the road from a park that had a gentle slope at one point. All the neighborhood kids taught each other how to ride a bike there. First, the kids would push the learner around on the bike on the flat part of the park. Then, we'd take the learner to the top of the slope, get him/her on the bike, give a push -- and by the time the learner got to the bottom of the slope, he/she was moving along upright and just had to start pedalling.
I wasn't a particularly brave kid, but I felt safe learning to ride a bike in that park because if I fell, I would land on grass. I still remember that wonderful feeling of coasting down that slope and then pedalling my bike for the first time in that park.
Maybe you could learn on a gentle slope in a park too.