Linear Algebra

Answer:

BANANAS FOSTER

The story in the first section of the puzzle clues some dates, which eventually leads to the main character's birthday. Specifically, the dad was born on December 19, 1972, and the mother was born in 1975, making their age gap three years. The main character was born in 2000, so their birthday is January 4, 2000.

Once this birthday is found, they can input the birthday into a Destiny Matrix chart calculator. An example is shown. Some numbers may differ across websites, but all relevant numbers will be the same.

Destiny Matrix for correct birthday

Matching the numbers found here to the diagram in the puzzle allows solvers to solve for x1 through x13. Translating each letter from A=1 to Z=26 spells out the answer:

ixiLetter
12B
21A
314N
41A
514N
61A
719S
86F
915O
1019S
1120T
125E
1318R

Reading the extracted letters by subscript order gives the answer: BANANAS FOSTER.