Hello Jonathan,

If you look at the diagram in the link below
http://www.astro.uva.nl/demo/sun/leven.htm
you will see what we call a Herzsprung-Russell diagram. This diagram plots the life of a star. Currently the Sun is at position B, that is where about half of the supply of hydrogen in the Sun's core has been used up. If you read through the webpage you will see what happens next for the Sun.