Hi Hailey,
Welcome to planDisney!
While the non-expiring ticket option is no longer offered for Walt Disney World guests, the tickets that were purchased under those conditions should still be valid and waiting for your use. Like you, my sister has non-expiring tickets purchased about 20 years ago that have days remaining. We were just talking about those last night, so your question is timely for me.
A couple of years ago, she was able to contact Guest Services at Walt Disney World and have those tickets added to her My Disney Experience account for future use. She had the physical tickets, so it was easy to share the ticket numbers and get them set up.
I recommend you
call Guest Services to ask a cast member to assist you. Or you can reach out using the
email form. Make sure you note in the subject line that you are asking about existing tickets without an expiration date. Please include any details about the date of purchase and the tickets that you can. If you, like my sister, have the physical ticket or a copy of it, have it on hand to expedite the process.
Good luck, Hailey! Wishing you an abundance of bonus Disney days.
Wilma