Baby Animal Puzzle for Isabelle

We bought this set of young of animal puzzle for Isabelle from Toys’R'Us last week and she likes playing with it. She was clueless on how to place them back into the slot but now she can do some pieces by herself. She will play with the set at least twice a day, and we don’t have to ask her to get the set out from the rack.

I wonder how long it takes for her to master it? By then, I will get more sets of puzzles for her.