If the audiologist says she would benefit from a hearing aid, then it isn't fine.
Age-related hearing loss proceeds gradually. Usually it's the high frequency sounds that go first - probably because the hair cells that detect those sounds lie at the entrance of the cochlea and so are more vulnerable; we're not certain of the actual mechanism in many cases.
Losing high frequency sounds first means that you lose unvoiced consonants: f, th, s, t. You speak English well: you don't really notice they're gone. The brain fills in the gaps using lipreading and context.
Then you lose a bit more. It's hard to hear k, p, sh. Loss of those high frequency sounds makes it appear that everyone else is mumbling but you can still "hear" because the vowels, the nasals (m, n, ng) and the other consonants are still reaching you. The brain works harder to fill in more gaps.
The -a- -a- on the ma-
The cat spat on the mac?
Of course not. Your brain has filled in those gaps using your previous experience.
But as you lose more and more of that hearing, the brain has to fill in more and more of those gaps. Listening requires more effort and there's less cognitive capacity available to actually process what you're hearing.
So maybe you heard it fine, but you forget it more quickly. You think you understood but it turns out that you missed a key part of the conversation. Nod and smile; you'll probably work it out later...
But with hearing aids in, your brain hears all the sounds and frees up the capacity to learn and to remember. And your brain gets used to processing the different quality of sound you get through hearing aids before the amplification level rises so it's not a huge shock.
We cope incredibly well with lots of missing sounds but it doesn't mean that our hearing hasn't declined.