Memorizing isn't hard, especially of 12 words seed phrase but don't do it the day before you fly, do it weeks before your flight. Exercise every day, repeat those 12 words every day for multiple times, for hours and it will be sealed in your mind. Read this 12 seed phrase like it's a song and it will be like a muscle-memory.
memorizing is out of the question. it's harder than memorizing a brainwallet. no amount of practice is going to allow to remember it for longer than a few hours if that.