Correct, if you are a member of a healthcare sharing ministry such as Medishare, you are exempted for the Affordable Care Act penalty.
On the Did you all have health insurance coverage in 2017? page click
None of us had it at any point, click Continue
On the Did anyone have a situation that waives the tax penalty for being uninsured? page
Scroll down to Wasn't required to get insurance
Click Health care sharing ministry member
Click Continue and follow the prompts and online instructions