What would I major in at college to become a webmaster?

Okay so i'm still in high school but my goal is to become a webmaster and create my own websites......

I guess i'd major in computer science but isn't that too general? there isn't really a web development major is there?

There are different courses you can take to become a webmaster. I list some of those courses:

-Computer Science and Engineering
-Computer Security
-Game Design
-Graphics and Multimedia
-Information Technology
-Networks
-Programming
-Software Engineering
-Technology Management
-Telecommunications
-Web Development

Most of these courses offer lessons about web. These courses are offered in different universities like the University of Phoenix and Kaplan University.

Well i am in India and i am a computer science student...
But it really doesn't matters to become a webmaster...
And there are no such courses here in India form universities wherein you can learn about webmasters !!
But yes being an IT or computer science student is far more better than any other courses if you are going for webmasters...
Because in these course you can learn the basics or i should say advanced parts of websites!!

computer science

I guess, Computer Science would just be good enough for you. :)

Computer Science may take you at most 4 years before finishing it. There is also a short course to take on this matter?

Well if possible .. you can go for short duration ... web development/designing crash courses!!
This will save your time as well!!

But if you really want to master all the disciplines in web you could also take a 4year course and continue it to master's school.

Such courses would help a webmaster do be a good writer. He will then provides information that will fill up the content of his web page or blogs.

Yup you can fill up the contents .. by conducting these courses...
But for the set up .. of web sites ... you got to know the basics!! which you won't find in journalism or mass media!!
Btu these courses are good for general awareness!!

Mass media is a broad field that can be use in web. But knowing the application when it comes to programming and web tools will help you make it through the field of computer and innovation.