You've accepted the top-vote answer of "just do it." YES, that's fine.
Now, I'll give you the next challenge: can you have a great lifetime relationship, as an adult, loving your parents... even though they may never actually agree with the choice you've made?
Why I ask: I'm not sure you're actually seeing this yet from a truly adult / "parents" perspective. (I am writing as an ancient denizen of the 'net, whose dad was like your parents, and am now a father and grandfather... ;) )
- You're an independent adult: proactively taking action, funding it yourself. You already know that your parents disagree with your choice.
- Your parents DID congratulate you on the success of your effort ("a short handshake, good job.")
I wonder: why were you surprised that they're not more supportive? They disagree with your choice. It's that simple.
Your question indicated that you expect them to change their mind? Why? You're not going to control their perspective. This is important to understand for a lot more than your choice of school.
One of my observations about both Asian and Western cultures: once people have taken action (including stating their perspective!) on a topic, it is VERY difficult for them to reverse course. Often at best they'll go silent, with a "let's forget about it" attitude. At best.
Your initial perspective on their disagreement was they are "treating me like I don't know what I'm doing and am still a kid." Likely reality: for whatever reason, they disagree with your choice.
Now, your perspective on their interaction with you is: "they have mellowed in their views and become more understanding." Likely reality: they still disagree with your choice but are no longer arguing with you about it.
I have had the privilege of knowing a number of amazing leaders, people successful in various fields. All over the planet. At first I was shocked to discover that a number of them have had -- even continue to have -- the same challenge you face with your parents. It's no longer a surprise. People just don't always agree on everything! And yes, because of that they often miss out on a very real blessing.
One amazing guy has led tens of thousands, influenced hundreds of millions. Yet his parents didn't understand, refused to even watch him speak, etc. They got together for family events, but his work and life calling was basically a taboo subject. This went on for many decades (!) AFAIK, in their old age they finally did attend one of his speeches.
What does it take to get people to agree on something?
The easy way: agree out of ignorance ("go along to get along")
But this is a topic of importance to you. Just like a marriage, or maybe politics or whatever.
To achieve unity there requires heart changes. For that:
- You need to understand their heart
- They need to understand your heart
- You need to live a life that overcomes the experience (of pain or joy!) that caused them to prefer a different choice.
- It may require a bit of a miracle :)
A bottom line bit of wisdom: people don't have to be rational and fact-based-logical about everything.