The most recent issue of Sky and Telescope had an article that 100 years ago most asrronomers thought that red supergiants like Antares were young stars and that as they aged they joined the main sequence and became more like the sun. Today we consider blue giants like Spica and Rigel as young stars. Stars like Rigel and Spica didn't start off hot with surface temperatures of 30000 degrees. They had to star off cool (red)and heat up to that temperature. So can we say that a red star is vey old or very young(on its way to becoming a blue giant).