I took the index of your words, converted the number to binary, additional three zeros, calculated the sha256 digest, took the first part of the hexadecimal to transform it to binary, added three zeros to your 8 digits in the binary and acquired 00000010011 which translates to 19 in decimal. https://webnowmedia.com/story4344351/helping-the-others-realize-the-advantages-of-bip39-mnemonic-phrase-tool