To be in the center or to be at the center

• I want to be in the center of the change.

• I want to be at the center of the change.

In the context, the statement makes that I want to be at the center of the changing society, I want to play an important role.

Which preposition do I need?

Solution 1:

At means place, position. So I'd say at the centre of change, or like you phrase it "at the centre of the changing society".

In means inside a whole or a context, or a situation, a phenomenon maybe. So I'd say in change, in society etc.

I think one should follow his physical understanding in such things.

Solution 2:

When I say at the centre, I think of a particular point, like the centre of a circle. On the other hand, in the centre gives a vague idea of some area surrounding the centre. So, if you're the main figure who is causing the change, it should be at the centre and if you're just a part of it, like say a member of a political campaign, you can use in. However, this interpretation may be too literal... I personally think at the centre should be correct for a more figurative understanding.