(question) Is learning design modeling a waste of time for website builders?

Hello. I have a question about website design. I am a self-taught programmer and I have a large website in my head, now I wonder if you're about to create a large website like stackoverflow(of course creating it once again sounds pointless. I'm just using it as an example) does the process consist of heavy design steps as in for example designing a desktop software? I'm not very familiar with PHP but I know OOP in other languages and some design patterns, however, I've never grown the backbone to go through the learning of "whiteboard/paper/diagram design modeling". Books like object design from Rebecca Wirlf or Code Complete and etc are out there and everyone suggests them. But I want to do only something that helps me toward my goal and not a blind waste of time. So I need to know whether reading one of these books will specifically help me toward my goal OR (sorry if this is harsh) website design is a solved problem for programmers, easier and less innovative than other software designs, and needs much less design modeling. I don't want to be carried away and try to learn something that takes much time but has little to do with my goal. But if I know it's worth it I'll definitely take the time. Thanks for your help.