Gomu Gomu no Mi/Techniques

Does oda love elephants cause he involves them so much. Examples:zunesha, zou, Bajrang gun

So my question come about from the side effect of shrinking after using giant attacks...

My reasoning for this is when luffy stops using the ability , he blows all the air out of this body, and this for some reason shrinks him to about the size he was from when he eat the fruit. because if he just blew out the air then he should remain his full sized adult self.(

Does that mean that luffy never grew to adult hood? and has instead just been blowing his own body up to the size he thinks his adult form should be?

) since he blew out all the air in his body it would revert back to his actual size without the growth air involved he would be as small as a child.

Any thoughts on this?