It takes courage to tell your parents what you actually want to study. It takes more to live with what you didn’t say.

Parents’ expectations usually come from wanting you safe, which makes disagreeing with them feel like ingratitude rather than independence. So people give the acceptable answer and then spend a few years living inside it. The conversation is one difficult evening. The alternative is a much longer bill, paid in a degree you did not want and a resentment whose source nobody can see.

Tell them what you want and why, with something concrete attached: the courses, the work it leads to, what you have already done in it. Expect more than one conversation, and start the first one soon.