I know Be to infinitive can refer to the future which can be controlled by people. Is this the same for be about to?

I'm about to turn 30.

Is this correct. The age cannot be controlled by people, can it?

Hi LiJ

You are right. To be about to refers to something that will happen almost immediately or very soon:

I was about to get on the train when an old friend ran towards me down the platform.

Thank you CB Emotion: smile

I'm still stuck with which my grammar book says that the future can be controlled by people when you use be to / be about to.

If it's true for all cases, I am about to turn 30 is incorrect because people can't controll thier ages. I think there could be exceptions, so I'm about to trun 30 might be correct and sounds fine to me, though.