I am sure you have a close, loving relationship with your niece. It sounds as if she’s fine when she’s at your house; it is a familiar and safe place for her. She is dropped off there by one of her parents, so she knows that her parents know where she is, and that is very comforting for her.

When you go to the classes, it’s another story. Your niece needs her mommy or daddy and nobody else will do. This is perfectly normal for a child her age. Your daughter is able to separate from you easily because she can clearly see that her mommy — you — knows where she is.

You can help her to understand that her parents know where she is, even though you’ve taken her somewhere other than the place they dropped her off. At this age, explanations through words alone will not be enough. She needs to know through experience that they have seen where she is. So have her mom or dad accompany you to the classes for a while; they may need to do this several times in order for your niece to be reassured, especially now that she has been so upset by going it alone the first few times.