Applying after career change

So I am applying for the 2027 class. I'm a professional journalist, been working in sports media for a little over a decade, but I am getting the itch for a change (going from one hyper-competitive industry with little growth opportunities to another - go figure). I've always been drawn to teaching and I think my real-world experience can help me transition into teaching high school English, media studies, writer's craft, etc, along with special education. My issue is that I'm almost 40, so it's been 15 years since I've been in university. My grades in certain courses may not match up to requirements - but they're also grades from a different person at a different time in his life. I'm nervous that these schools are just going to look at the 15-year-old transcripts and throw them straight in the trash. Am I right to be concerned? TIA