I think she’ll probably remember if you write it in grade one. Grade one is A-to-Zed or A-Z letters and numbers. So for example, instead of writing birthday as be, i, r, th sign, day sign, you write everything out fully, you should be good.

I startted learning braille at age 4, so I don’t think I will ever forget how to read braille unless I have some medical condition that causes me too.

It's very unlikely. I once stayed away from braille for years, but still remembered and was able to read reasoniblly well and fast when I tried it. But, who knows, this person might have forgotten. Depends how long she spent time with braille, how much reading she did in her past with braille I suppose.

We still have to occasionally use braille at various places, be it public accessible signage, or whatever.

I am probably similar to her in this respect (haven't used Braille on a regular basis since my late-teens, despite growing up with it), and it is still quite impossible for me to lose that knowledge. Once told someone that the only thing that might make me forget Braille would be a head injury or stroke. It could depend on the circumstances of her upbringing: I was raised in a time when learning Braille was compulsory, and the idea of giving laptops and iPads to children and having them use dictation for their assignments had not even been conceived of yet (didn't use any form of technology for writing and reading until I was nine or ten.) If she is a younger person it's certainly possible that her instructors put less of an emphasis on Braille, and in that case she would have a more basic understanding of the code, but forgetting, I think, is still nnot likely if you are mentally normal and blind from birth.

I doubt she’ll forget it if she grew up with it.

No probably not.

I wasn’t born totally blind but effectively so. I was taught braille at 5 years old and lost my vision at 8. So I can’t forget it even if I didn’t use it daily.

I mean... Kinda, lol
I learned it 20 years ago, hated it, stopped using it, and only remember like... Half the basic alphabet and one contractions I think 🤣

That’s a great question

Chances are she will remember it, or at least remember enough to figure out what it says. But she may read it very slowly, kinda like a sighted person would do in a similar situation.