You should start with the oldest first. Start with 2013 and work forward. There may be things in one year that will carry forward to the following year.
TurboTax for 2013 is no longer available. You can purchase TurboTax software for 2014, 2015, and 2016 at the following link.
https://turbotax.intuit.com/personal-taxes/past-years-products/
Returns for past years cannot be e-filed. You will have to print the returns and file them by mail. Mail each return in a separate envelope.
