Rules question

Playing solo just now and had the following hand happen:

Dealt a hard 14. Dealer showing a 10. Checks for blackjack and it doesn’t register. I hit and get a 7. Dealer flips over and shows an ace for the blackjack.

Pit boss says the original hand stands and they kept my $100 bet. I argues that it should have been a push. Not only did I match the dealer but took an extra card from the deck.

How should casinos handle this scenario and is there any discretion that a pit boss can make to push the hand?