I don't think Fredrika's really lying to herself. She probably genuinely believes that Desiree is going to come see her, which of course she eventually does.
She's idealizing Desiree's life, but she was very young when they toured together. She probably doesn't remember much of the grit of it all. Anyway, she's only fourteen. Of course she wants to hold her mother as an idol.
But she is, however, trying very hard not to admit to herself how much she misses Desiree. At least that's the way I see it.
I know you.
I know you.
I know you.