Yes, you should start with the earliest year and proceed from there.
You
can only use Turbotax Online to file for the current year (2017)
taxes, and not for any other year.
If
you would like to use TurboTax for 2014, 2015, or 2016 you will need to
purchase the Desktop Version for the specific year for which you need to file a
return. You can purchase the Desktop version at this link:
http://shop.turbotax.intuit.com/personal-taxes/past-years-products.jsp
You
are also able to download the Forms and Instructions free from the IRS web site
at this link:
http://www.irs.gov/app/picklist/list/priorFormPublication.html
