I think you may mean "My opinions are not me", or "I am not my opinions" gives you the space to separate your identity from your thoughts, giving you the freedom to change.
This happens excessively in politics. Suddenly a huge chunk of a political faction will have the same “opinion” on a complex topic they have no day-to-day interaction with or previous educational coverage. When you try to dig deeper on these topics people hold such fervent “opinions” on, it turns out that it’s just a restatement of what they heard from a friend/talking head.
What I also find interesting is that this idea is rather old, it can be found in Christianity, for example, where "devil is tempting you", that is thoughts and wishes you have might not be your own (but from some demon tempting you). It may sound a bit silly in modern times, but it boils down to the same idea.