I took the index from the words, converted the number to binary, included a few zeros, calculated the sha256 digest, took the very first Portion of the hexadecimal to transform it to binary, additional 3 zeros for the 8 digits of your binary and got 00000010011 which translates to 19 https://infopagex.com/story4158475/little-known-facts-about-bip39-words