I took the index of your words, transformed the selection to binary, included three zeros, calculated the sha256 digest, took the first Component of the hexadecimal to transform it to binary, added 3 zeros into the eight digits of the binary and got 00000010011 which translates to 19 in decimal. https://bouchesocial.com/story20751397/facts-about-bip39-seed-phrase-word-list-revealed