By age seven I used to comb my hair for performances just pull my hair up into a bun. Granted it wasn't a very intricate hairstyle. Still to be that responsible and disciplined at age seven is unusual.
Trust your gut instinct over spreadsheets. There are too many variables in the real world that you simply can't put into a spreadsheet. Spreadsheets spit out results from your inexact assumptions and give you a false sense of security. In most cases your heart and gut are still your best guide.