I was about 5 or 6. My kindergarten teacher noticed I was exceptionally quiet, so she asked my parents if they'd considered if I was deaf or hard of hearing (they never really thought about it. The doctor who delivered me told mom to watch out for hearing problems because one ear was smaller than the other, but after that, they didn't think much of it). They took me to the Audiologist upon my teacher's suggestion, and they confirmed I was hard of hearing and got me set up with hearing aids. Susan was my audiologist then and I still have her almost 17 years later, lol.
I still remember the wonder the day I got home with the package of hearing aids and after mom helped me put them on, I ran around the house clapping my hands and telling mom to "listen! Listen!" to the sound echoing off the walls. Probably one of the brightest moments of my life.