We have full custody over our niece. what do I mark. adoption or what.

[tclwharton]

I think it was final in court in year 2017 but we had her all year at our house

[Texas Roger]

Since the adoption wasn't final until 2017, enter her as your niece. On the screen that asks What's your relationship to [name]? answer that she is someone else you support. In the drop down box, choose niece.