I started today and got this, is it good..?

It's really good for pushing the story. Arena fell out of the meta a while ago, so you can't win if the opponent has the latest cookies.

Congratulations!

Slurp! To obtain a Legendary grade on the very first day, you must possess truly brilliant luck, hmph! The Fire Spirit Cookie will be a benevolent reinforcement, lending meticulous firepower to your early story progression. May you wield this cookie's fiery power well on your journey through Asteria, hmm!

It was good.