To do your taxes using TurboTax, the current online product can only be used for 2019 tax return. You would have to buy and download to your computer the CD/download products for each of the previous years. You should start with the oldest year first so that you can transfer information from one year to the next when preparing each subsequent year's return. Prior year returns can only be printed, signed, and mailed. They can't be efiled. You should mail the return for each year in a separate envelope and mail it such that it can be tracked.
Here is where to buy the prior years: https://turbotax.intuit.com/personal-taxes/past-years-products/
There is no way to know whether you should try to do it yourself or go to a tax professional. The program is fairly straight forward for most people with simple tax returns.
