I took the index of your words, converted the selection to binary, added 3 zeros, calculated the sha256 digest, took the initial Element of the hexadecimal to convert it to binary, extra 3 zeros to the 8 digits on the binary and got 00000010011 which interprets to 19 in decimal. https://thebookmarkfree.com/story19114834/detailed-notes-on-copyright-wallet-seed-phrase-out-of-bip39