I have interesting experience with this subject.
Client of mine (I am a success coach) have done some work on growing taller, and after few days her boyfriend (who didn't know she was working on it) told her that he perceive her as much taller (very convinced in what he was saying
.
My feeling about it was that in her own reality she was taller and that her goal was achieved regardless of how "objectively" tall she is.
Her desire to be taller was there to make people from her reality perceive her in specific way (that was deeper intention behind her goal).
Her boyfriend was probably most important person concerning that goal. For her that experience (her boyfriend perceiving her like that) was experiencing the achievement of her goal.
And explanation of how was that possible could go from herself being objectively taller (that she didn't as she measured herself afterwards
to the possibility that with changed inner reality (as the result of the work she has done) made her standing in different way (more erect).
Anyway, I believe that by changing our inner reality we are getting changes that are really only ones that matters. So, do your affirmations (or any other technique you are using for changing your inner reality), and create the life you truly want.
Yours,
Henry