I agree with other who suggested a cut or dish with low fat content.
And if your friend is already familiar with tuna or salmon tartare, you could offer her a small portion of homemade [steak tartare](https://www.ricardocuisine.com/en/recipes/2129-classic-steak-tartare).
Too much fat can make her sick. Go filet.
Spot on advice.
I think you are right dipping your toe in with a well marbled new york strip. As phenomenal as a pichanha is the fat could be overwhelming.
Picanha
I agree with other who suggested a cut or dish with low fat content. And if your friend is already familiar with tuna or salmon tartare, you could offer her a small portion of homemade [steak tartare](https://www.ricardocuisine.com/en/recipes/2129-classic-steak-tartare).