Funny you'd phrase it that way. In a sense, the Sun did start up that way.
Astronomers are pretty sure in general how stars form.
A large gas cloud collapses. As it collapses, it flattens out and starts to rotate. The star forms out of the center of the disk. The onset of fusion heats things up a lot . Normally, when you heat up a gas suddenly to millions of degrees, it wants to expand very quickly.