Your picture isn't showing up, but I know that fiberglass will yellow when exposed to sunlight. So my guess is that you need to paint it.

Thank you clt3. I’ll see if I can get the picture to upload again...

here’s an example of the door.

I think this is a question for the manufacturer. They probably have some kind of research on their white doors yellowing. Perhaps rethink the white door if there is a chance of major yellowing in 10 years. Or sooner. Seems weird to me to spend the extra dollars for a fiberglass door and then paint it because it yellows. Choose another colour and go with maintenance free (maintenance free is the biggest selling point for a fiberglass door).

Choose a steel door in a color you like . IMO a factory finish will always last longer.

Double check with the manufacturer, but it might only have primer on it.

Yes, it needs to be painted/ finished.

Feather River install instructions say that it must be finished w/in 6 months of installation.