Refer the meaning of l sabel's words ,'They know l .... At the festival (lines 3-6)

"Oh come off it Thami. Don’t be like that. They’re always nervous when it comes to me. But this time it happens to be genuine interest. I’ve told you. I talk about you at home. They know I have a good time with you . . . that we’re a team . . . which they are now very proud of incidentally . . . and that we’re cramming like lunatics so that we can put up a good show at the Festival. Is it so strange that they want to meet you after all that? Honestly, sometimes dealing with the two of you is like walking on a tightrope."

Isable is referring to the fact that her parents know she is working with Thami and Mr. M, and that their reservations are based upon worry... not about who she is spending time with. They are worried about her, as are all parents when it comes to their daughters. In context, Isabel is happy about the fact that her family wants to meet Thami... that they are proud of her hard work, as well as the work that she and Thami are doing as a team. Thami's rejections and reservations irritate her.