The first teeth you get immediately after birth just like you get your first opinions from your parents and social environment. Later in life you develop your own opinions just like you lose your original teeth (called milk teeth) and develop more permanent ones that are probably gonna last you a lifetime.
Ehh, personally I like thinking over things and forming opinions. I don’t frequently share opinions I don’t deem important, but I have 'em! Plus realizations in one area that seems small can have impacts on the opinions that are more important to you.
I feel like I should have majored in philosophy.