I took the index of your words, transformed the selection to binary, additional a few zeros, calculated the sha256 digest, took the main part of the hexadecimal to transform it to binary, extra three zeros into the 8 digits with the binary and got 00000010011 which interprets to 19 in https://ztndz.com/story22139471/the-ultimate-guide-to-bip39-seed-phrase-github