Building by first ever deck and I got a question | tcgmode

I've watched a bunch of YouTube videos and I think I've built the deck well. I've been goldfishing it and a few times I've run into an interesting question. Turn 3-4 I have 4 mana and Arasta of the Endless Web in my hand. Assuming no other big reason to play my commander do I play Trostani or Ara...