Moss'd in Space (#1) by Rebecca Thorne

From Bramble:

Torian Razner finally bought a starship, and contrary to Amelia's assessment, it was not "a meteoric sign of stupidity." Sure, the alien starship may have been abandoned for a century, and it may be covered in moss now... but it's Torian's ticket to freedom, regardless of what her ex... ah, captain... said.

Except Torian's first flight reveals a surprise passenger: the moss is actually an organic computer with a snarky attitude and serious abandonment issues. The target of its loathing? The immortal alien who built it (and then parked the starship, with Moss inside, and forgot about it). The same alien who just found Torian and accused her of "stealing" the ship.

It's entirely possible that Amelia was right about this meteoric stupidity.