Aubrey is growing up and losing her canine teeth.
As you can see here, her top right canine is darker at the gum line, indicating it is no longer attached at the root. You can see the lower right canine has already fallen out, and the permanent tooth is coming through the gums.
Here is a video of her wiggly upper left canine.
On the left side, you can see that she has both baby (deciduous) canines.
We can guesstimate age using teeth in a puppy. All 4 adult canines should be fully grown in by 6 months of age. Aubrey just made 4 months, so she’s a little ahead of schedule.
Just one last silly picture of this loveable puppy: