I need to finish filing my 2017 taxes in order to be able to file my 2018 taxes. Where should I go?

[VolvoGirl]

You should be able to file 2018 before you file 2017.  Or do you know you will need something from 2017 like a Capital Loss Carryover or Depreciation, etc.?  

To efile 2018 you need the 2017 AGI but if you didn't file 2017 your AGI is 0.

How to finish a prior year online return   <a rel="nofollow" target="_blank" href="https://ttlc.intuit.com/questions/2559403-how-do-i-finish-a-prior-year-return-that-i-started-in-turb...>

[Ashby]

In order to file a prior year tax return, you must purchase the TurboTax download version for the year you need(2017). TurboTax Online is only available for the current tax filing year. 

Here's the instructions on how to get the 2017 TurboTax product

Tax years 2015, 2016, and 2017

1. Select your TurboTax product for the year you'd like to file. (Unfortunately, TurboTax Online is only available for the current tax year.)
2. Select your operating system.
3. Purchase your TurboTax product.
4. Download and install your TurboTax product.
5. Complete your return in TurboTax. We'll guide you through the process.
6. When finished, print and file a paper return through the mail. (Prior-year returns cannot be e-filed.)