I'm even better at side planks and bridges than front plank.
My balance issues are very specific to direction and movement, totally based on my crappy spatial orientation and visual perception.
The comments about learning to do stuff as a kid is so true. I was such a timid kid about this stuff, and it was reinforced by my family. By the time I wanted to do certain things, the learning curve was really steep.
So, if you have kids, encourage them to be daring.