Meditation is not about memorizing and seeing how many verses you can quote that is for kids. Meditation is prayerfully saying the verse to God and asking Him how He wants to use it in your life to conform you to His image. Meditation is for life change. It is the very essence of transforming your mind.
If you can’t memorize no problem just write out the verse and carry it with you.
Are you obeying this command to meditate?