In the comics, Nick Fury is indeed shown as black. This portrayal has been consistent over time and is an important aspect of the character's representation.
Yes. Nick Fury is black in the comics. This has been a consistent part of his character design and has been maintained throughout various comic storylines and adaptations.
Percy would probably be a bit wary at first. He's used to the demigod world and Fury's whole S.H.I.E.L.D. thing would seem really different. But Fury would be all business. He'd likely be sizing Percy up, trying to figure out how to best use his powers.
The age of Nick Fury in the comics isn't fixed. It can change based on different story arcs. Sometimes he's shown as a seasoned veteran in his late 50s, while in others, his age might be presented differently depending on the creative choices of the writers and artists.