I'm not sure how much this will help because while I have a similar condition, I can't be sure that what's causing my central vision to go is the same as what's happening for you. But I definitely know what you're feeling because my prognosis has always been "it might get worse, it might stay the same," which kinda sucks.

From the time it became noticeable, a little dot in my central vision, to now, about six years later and my central vision loss is about the width of three of my fingers held out at arm's length. it doesn't sound like much but it's most of my central vision at this point. I'm in my early twenties. Hope that helps- it really is different for everyone though. Find something in your life that is constant- your hand, a grid on a piece of paper, something in your house like a smoke detector or a painting, and look at it every once in a while. That's kind of how I gauge my progression ( X many years ago, I could see the numbers on a clock when standing X feet away and staring directly at the center, and now I can only see the outer frame, for example)

Sorry I have to remove this as asking for medical advice is prohibited on the sub.