My sister passed away last year and left a portion of her estate in an irrevocable trust to my daughter which I am a trustee. The trust received a total of $636 from rental property investments for the 2017 tax year. I received K1 forms for those rental properties. Do I need to even file a tax (Form 1041 ?) since she is just 17 and/or since there was just $636 of income from the investments. Any advice is welcome. Thank you.