decisional -- Kristin

de·cision·al adj. Synonyms: decision, conclusion, determination These nouns denote a position, opinion, or judgment reached after consideration: a decision unfavorable to the opposition; came to the conclusion not to proceed; satisfied with the panel's determination.

The American Heritage® Dictionary of the English Language.

Kristin is assertive and firm and I'm guessing that, like many mothers, she's the decisional force in the family.