I recommend making the poke bowl right before serving for the best texture and flavor. However, making poke bowl ahead of time with a short marinating time also helps the fish to absorb flavors. You can marinate it in advance and keep it refrigerated (for up to 24 hours), then assemble the poke bowl until it's ready to serve. However, avoid marinating it for too long, as the fish may become overly seasoned or lose its delicate texture.