There’s a revert sister I nearly married over a year ago but she said she wasn’t ready for marriage. I still think about her daily, struggle to consider anyone else and truthfully only want to marry her. Is it permissible to contact her and ask if I can wait until she’s ready? What would you advise?

Contact her wali, not her. It's not permissible to talk to a woman alone, and how do you even have the ability to do so? We can contact her wali and see, and pray Istikhara, and ask Allah Subhanahu wa Ta'ala for what is best for you in your deen, dunya, and the hereafter. Sometimes you might wish for something and desire something that would be one of the worst things for your life, and you should be happy and content that Allah is pushing her away from you.