I took the index from the words, transformed the selection to binary, included three zeros, calculated the sha256 digest, took the 1st Section of the hexadecimal to transform it to binary, additional 3 zeros for the 8 digits of your binary and obtained 00000010011 which translates to 19 in decimal. https://siambookmark.com/story18984474/fascination-about-invalid-bip39-phrase