The sun is almost halfway through it's life cycle; well before it becomes a red giant. The sun has been alive for about 4.6 billion years. To be exact, 4.57 billion years. People believe that in 4.6 billion years, the sun is going to swell up into a red giant, which ill engulf the earth. In the picture below, people would say it is a pretty accurate theory. You can learn more about a star's life cycle in the tab at the top labeled "Life Cycle of the Sun". The sun has already passed the phases of a stellar nebula, a protostar, and now an average star; a.k.a. yellow star. Also learn about that in "Life Cycle of a Star".
Life Cycle of the Sun.
The sun is where in it's cycle, and what is it like today?