Per the PHB: "Half-orcs exhibit a blend of orcish and human characteristics, and their appearance varies widely. Grayish skin tones and prominent teeth are the most common shared elements among these folk."
Grey is the most common skin tone tone, but browns and greens appear a lot in WotC art - There's plenty of official WotC key art showing green half-orcs in 5e. The DM of my game chose the appearance of this character, as she's an NPC - trust me, the art would have been a LOT easier for me if she were grey.
You keep doing this for OP's goblin OC as well. There's lots of official WotC art of green goblins, including the current Monsters of the Multiverse art that's being used as the default art for the goblin lineage.
It's kind of rude to tell people that their character designs aren't valid just because you don't approve of their choice of skin-tone.
Looking at her sheet, she has Animal Handling, Athletics, and Nature, plus proficiency with heavy armour and most weapons (although her weapon of choice is that greatsword.)