I took the index of your words, transformed the number to binary, added three zeros, calculated the sha256 digest, took the primary Element of the hexadecimal to transform it to binary, additional three zeros for the 8 digits on the binary and bought 00000010011 which interprets to 19 in decimal. https://bookmark-media.com/story19003197/considerations-to-know-about-bip39-word-list-pdf