I took the index of your words, transformed the selection to binary, additional three zeros, calculated the sha256 digest, took the main part of the hexadecimal to transform it to binary, added three zeros to the eight digits on the binary and got 00000010011 which translates to 19 in decimal. https://mysocialguides.com/story4197560/bip39-seed-phrase-mnemonics-generator-an-overview