Disappointing your parents with a brave choice beats disappointing yourself with a safe one for life.

Disappointment from other people has an end to it. It fades as they watch you take the thing seriously, and within a couple of years it usually turns into something else entirely. Disappointment in yourself does not expire, because the person holding it never leaves the room. That asymmetry is the whole calculation.

None of which means ignoring people who love you. Hear the concern properly, answer the practical parts, let them see the plan. Then make the call yourself, because you are the one who has to live inside the result.