Reeslynn's new trick

First my update.  I am feeling well enough to say I am hopeful that I may be tolerably better soon.  We have been extremely cool and Saturday, high of 58, I got in the woods for a 10 minute walk and actually pulled a few weeds.  Sunday was grocery shopping after church and a tired day. 
Reeslynn has developed a strange new habit.  She growls.  A deep low gutteral sound and she adores the reaction she gets from people when she does it.  Little stinker is pretty smart for a 3 month old.  At first, I thought something was wrong with her and had to listen to her little lungs.  Now, I am more relaxed, though I must admit I did wait for her head to spin around last week when she first started this.  I asked my family doc about it and she said some babies do this although usually not this young.  She think they like how it feels in their throat and then enjoy the reactions of the people.  My husband thinks, like Grayson, that she spends too much time with dogs.  Grayson used to growl when he was mad at us, though he was much older than Rees.