The problem with knowledge on the Web is that it's mixed in with a lot of noise, and, frankly, there's just too much of it clamouring for your attention.

So, sure, you can Google the hell out of CSS, and clearly that's good enough to build Web pages.

But equally there are a gazillion posts about everything, and no considered, coherent, path through it all.

A university maps a well-trodden, and hopefully well considered path through the knowledge. It leads you to places unknown, and sparks interest (and understanding) beyond just writing code.

For example you might randomly hear about P versus NP, or NP Complete, and decide to follow up on the web about that. Chances are though this might be the first time you've come across this. But I'm pretty sure it'll come up at college.

A degree course guides you through the knowledge, taking you places you didn't know existed. Over the long run this foundation makes it a lot easier to grow and do more than just "write code."

If you have the opportunity I recommend taking the time to do some formal study.