A life story packing in sex appeal from page one? (2,6)

I believe the answer is:
ab initio
'from page one?' is the definition.
I can't judge whether this definition defines the answer.
'a life story packing in sex appeal' is the wordplay.
'life story' becomes 'bio' (short for biography).
'packing' means one lot of letters goes inside another (some letters are packed inside).
'sex appeal' becomes 'it'.
'in'+'it'='init'
'bio' placed around 'init' is 'binitio'.
'a'+'binitio'='AB INITIO'
Can you help me to learn more?
(Other definitions for ab initio that I've seen before include "Undercoat for metal/wood" , "From the start - in Latin" , "from scratch" , "From the beginning in Latin" , "from the outset" .)
