"Not quite so much restrictive as...I should not wear these clothes when not in battle." Shuri did not desire to wear out these clothes, in case a real battle ensued at some point. The point of her battle gear? To battle.
"I think I shall ask my pseudo big brother first, as some of his t-shirts may fit me. But, I appreciate the theatre suggestion. I forgot about that place. Well, I feel quite happy that your clothes still fit you." Mostly because I couldn't handle the complaining if they didn't, she thought.