Since the original Aladdin story was set in China, I thought it'd be brilliant if she was an expert in Fu Jow Pai aka the "Tiger Claw School" of martial arts (this also doubles as a reference to her pet tiger, Rajah). I also think that it'd make sense if during her studies, she would've developed a friendship with Mulan similar to the friendship of Ryu and Ken from the Street Fighter games.
Her being somewhere in her twenties comes from her voice actress, Linda Larkin. Linda was 22 when the movie premiered so I thought that should be this version of Jasmine's age here as well. But then again, the movie was over 30 years ago so I could make her to be in her early 30s.
As for her possibly wearing a hijab, I'm not entirely sure about that. The original Disney movie had an implication that her family were practicing muslims due to her father say "Praise Allah!" when she announced her plans to marry Aladdin, but there's never been any other references to their possible religious beliefs in any spin-offs or sequels. Jasmine's also someone who bucks tradition so she could very well be someone who sees no reason to wear religious headwear or even be a religious person in the first place.
