With all due respect to what could’ve been a better way to deal with the situation: what happened, happened. You can’t change that. Working towards being more prepared for next year’s application is the best thing you can do for yourself right now. Some time ahead of the call, emailing them and informing them will probably take a huge weight off of your shoulders since they’ll already know and you won’t be panicking about what’s going through their mind (it’s harder when they don’t see your face, so informing them will make it easier on both sides). Assuming they don’t have an age limit, working on yourself and trying next year is a perfectly fine idea. Whatever happens, you will be okay.