As a beginning programmer, should I favor building my own libraries over using 3rd-party libraries?

Question

As a beginning Python programmer, is it a good idea to build and understand my own libraries before jumping to advanced 3rd-party libraries that contains the functionality I need?

Some projects (e.g. web frameworks like Django) are probably too large for this approach. But other projects (e.g. Web Crawlers, graph libraries, HTML parser) seem to be feasible.

I worry that early reliance on 3rd-party libraries would stunt my growth.

Note: this question and this question seem to focus more an experienced programmers, who are probably more focused on the efficiency of reuse than the learning benefit. My question, I think, is focused on beginners.