I had a classical guitar warm up guide which had an introduction by Robert Fripp. He included a short list of tips and one was that the value of finding a great teacher is that they can connect you to the culture of the instrument (I'm paraphrasing b/c I can't find any references). That's something that's difficult to replicate on your own.

That said, you can learn a lot on your own. There's no right or wrong approach so you should feel free to take the route you're most comfortable with.