He also said whatever, not whoever. And his vow was that 'whatever.....shall surely be the Lord's'.
Had it been an animal, that would have been an actual sacrifice, since it was his own daughter, then he 'sacrificed' her purity to remain faithful to God.
Or at least, that works for me. Believe how you wish.
Crusty, I think the original manuscripts were inerrant, the copies no.