The waiting is very stressful. I can't help you on the reading of the MRI as there seem to be different ways to express things on MRIs and I am far from an expert. I am much older than you and therefore in a slightly different position in a lot of ways. I am not a doctor, but I will share what I have learned.
First, like you, I started off with a mild hearing loss. (It has progressed but my understanding is that it does not only do so.) One of the "weird" things about these tumors though is that increase in symptoms is NOT the same thing as increase in size. My tumor has not grown. My hearing is considerably worse and my tinnitus is somewhat worse than when I was diagnosed a year ago. As my doctor commented, my tumor is biologically active even though not growing.
Will you lose your hearing in that ear? Hard to say. Can you find ways to mitigate the effect if you do lose your hearing in that ear? Well, some of us adapt more than others. I am an amateur musician so the hearing loss has been tough. But I continue to take piano lessons and practice. I continue to listen to music but I got headphones that somewhat mimic stereo sound in only my good ear. I do lament that music concerts seem less nuanced to me.
When you go to the specialist for the first time, they likely will not know whether the AN is growing. Only time will tell you that for sure. But even if it is growing today, it may not be tomorrow, and even if it is not growing today, it may grow tomorrow. Welcome to the world of uncertainty.
As for balance, if you treat the AN, your balance might get worse. If you don't treat the AN, your balance might get worse. If you have surgery, your balance might get worse. If you have gamma knife, your balance might get worse. if you watch and wait (which is very much a treatment option at my age and, realistically, less of a good treatment option at your age(, your balance might get worse. But it might not. Also, you should know that physical therapy for balance can make a difference.
And don't assume that you will not be able to do the sports you do now. I am almost 70, I have osteoporosis, I have some minor balance (for which i compensate well) and I still hike. I snowshoe. I am more limited by my back issues than my AN.
You might want to take a look at Emily's blog. She was diagnosed with an AN when she was in her late twenties and deals with some of the issues that you are raising. She also lives a very full life.
https://luckybraintumor.comGood luck!