I took the index of your words, transformed the variety to binary, included a few zeros, calculated the sha256 digest, took the main Component of the hexadecimal to transform it to binary, extra 3 zeros on the 8 digits from the binary and received 00000010011 which translates to 19 in https://macrobookmarks.com/story19093491/bip39-phrase-generator-can-be-fun-for-anyone