M.I.
you do what feels and works best for your family. its not about her "learning" to sleep through the night. that isnt something you "teach" a child, its something you "nurture". good sleep habits come from the knowledge that parenting doesnt stop at 7 pm.
do what feels right for YOU. ignore the "rules", ignore people who say you will "spoil" her (milk only spoils when someone neglects to care for it properly), do what you know is best.