How to use a word "begrudge"

I learnt a word begrudge on the previous post.
Well, well, ----

Yesterday a student came, who is 8 years old. She also take dance lessons at a place.
She said.
"Hey, Mieko-Sensei guess what! I thought my dance teacher must have been 23 years old, but she is 51 years old. I can't believe it."

I said "I can't believe it either."

Her mother is probably in her 30's. Even even though the dance teacher "looked" younger than me, it cannot be helped, but the teacher looked younger than her mother.  "I begrudge her (the teacher is she.) youth." ( I know my limitation about my looks.)

Well, I don't know how she judged that she would have been 23 years old, but anyway the other day she knew her correct age from the teacher directly.

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Well today I went out to meet an owner at cafe with lunch. The bread was really delicious.

It's the time for my lesson. First a 5-year girl will come. What will she tell me today?