Honestly, not even the doctors can tell you that. The Avastin shots have helped me a lot, aif your doctor thinks they are appropriate, I recommend them. Not fun, but a medical miracle. I'm 48, was into bifocals by aged 6. Vision about -13 in each eye. Good luck! You good be good for years and years yet!
Myopic degeneration (dry) does not mean you will necessarily lose your central vision. You confuse it with macular (wet)degeneration and is when Avastin shots are used to treat.
You might/will get some skotomas but presuming loss of central vision is wrong.
These should be your good news of the day :)