Quote from: the joint on Today at 07:01:45 PM

I just wasn’t sure if users had an option to select their own seed phrase back then.

Technically, it's possible to have a wallet with your own selected words, but since people can't be good at generating random words, that's not recommended. It's better to let the words to be selected by the wallet.

Anyway, if you want to have your own words, there are two requirements.

1. The words should be selected from the BIP39 words list.
2. The 12th word should be selected in a way, so so the checksum is passed. This can be achieved with brute-forcing the 12th word.

After having your own words, you can import them into any wallet supporting BIP39 seed phrases.
Electrum allows you to import the words, even if the checksum is failed. But it's recommended, because it's not a standard seed phrase.

As already said, it's not recommended to select the words and you should let the words to be generated randomly. It would be more secure if the words are generated by a open-source wallet.