What is BBA?

I often use ”mercari”, the Marketplace app, to sell and buy items.
 One day, I bought a secondhand book from an individual. 
Since I haven't heard from the seller for a while,  I checked her profile in the app.  There I found it saying,
“I'm sorry I might be late for replying because I am BBA.”

  Do you know the word “BBA”?
 I’d never heard of it, so I quickly Googled the word and I saw at the top of the list saying,

“BBA stands for Bachelor of Business Administration.”

“Wow, it seems she's a very smart and busy person.”
 I understood why she was late to reply.

 Then just when I closed the window, the second headline of the list caught my eyes.
It said,
“BBA means ば〇あ.”

ば〇あ is a very dirty Japanese word, so be careful not use it to others.

“I got it!”
 That makes more sense to me.
 She meant that she's so old that she can't react and reply during the deals.
 I continued reading the article and it said “BBA is one of the net slangs and is used mainly among women in their twenties or thirties.
 They use it in order to deprecate themselves towards younger people than them.
Does that mean it is cheeky for women in their 50s like me to use it?

By the way, I thought there must be a word meaning じ〇ぃ.
I looked it up on Google and soon found it.
What do you think it is? 
Yes. It is “GGI”.
According to the article, however, GGI isn’t used much less than “BBA”.
Anyway, I am no longer even “BBA” because I am a person who feels hassle to convert the text from hiragana to the alphabet.