So, in essence, Aisha is between 18-20 years old mentally, but instead of having grown up with other kids, and developed naturally with them, she spent all her time "growing up" alongside other adults (Joe, Garment, Matrix, Joe's dupes, Fleet, Survey, Tetra and Tybalt). She also has had access to way more information about the world that the average teen, as well as instruction on Art, Physics, Engineering and Fashion. At this point, she could probably hold a decent conversation with Hawking and not be too stressed about it.
She's lopsided in that all of her learning was from significantly advanced points of view, and relating directly to another teenager now would be somewhat problematic for her. Understanding them would be possible, but empathising with them would be much more difficult. Even with all of her advancements, Aisha is still gonna Aisha, just in new and different ways.
As far as her being sheltered? Nah, not really. She's been training with Tybalt and reviewing current events with Survey. I'd be more worried about the rest of the world being protected from her. She's probably got a better handle on what's happening around her than any other person in BB regardless of age. Not what I'd call even a little bit sheltered. Extrovert extreme, you just can't remember interacting with her when she's done