Can I create my own 24 word system using JavaScript or Ruby?
You have reduced the level of security by making it so that an adversary only needs to figure out your three-word phrase rather than your 24-word phrase. Assuming 170,000 English words from which you derive your phrase, your three-word phrase only has 52 bits of entropy. In practice, it will probably be less than this because your set of words may not be sufficiently diverse or your choices may not be sufficiently random.
Of course, the adversary also needs to find the encrypted seed which you have sent to your friends, but that's a different matter, and socially engineering one person is still easier than brute forcing a 128-/256-bit key space, let alone socially engineering 1 of 20. Assuming the probability of the adversary successfully attacking a particular friend and getting the encrypted seed is 0.1%, the probability of them succeeding when you have given 20 friends the encrypted seed is 1.98%.
You're better off just using a BIP-39 seed phrase, writing it down somewhere (not sharing it with your friends) and using &quot;apple pisces steve&quot; or whatever as the BIP-39 optional passphrase, which you either remember or also record somewhere (not as important where, as long as the actual 24-word seed is stored in a safe, offline location). This would effectively result in a 27-word seed.
Consult this video by Andreas Antonopoulous for other reasons why you shouldn't devise your own schemes, and what you should do instead: https://youtu.be/jP7pEgBpaO0