There are approximately 6 trillion miles in a light-year, so the distance we need to go is 6 trillion miles / light-year times. 4 light-years is equal to 24 trillion miles. So, this whole would take 1.2 billion hours. There are 24 hours a day and 365.25 days per year, so this time in years is 137 thousand years.
Be frank. Some established designers use no or little computer software in their work. Others rely heavily on technology (CAD). Simply explain how you work. If you are an efficient designer, your use of computer software will not be relevant.