I'm not sure a general 'ignore it' would be what I'd have ever said.
Agreed with the whole post, but especially this.
I'm a big fan of ignoring some behaviors as a way to extinguish them. If the dog doesn't get a reward, the dog won't do it. I would probably not ignore, but "ignore" that behavior--stand up to where she can't reach me, cross my arms and look at the ceiling. If her goal is to get your attention, she'll learn quickly that this doesn't work.
However, this has to be tied to you figuring out why the dog is doing that, and meeting those needs in other ways. If this is not done, then the behavior is its own reward--eventually she will pull your hair hard enough that you have
to react, or even if you don't, the pulling itself is fun--it's basically tug except you're not engaged, after all.
2-3 30 minute walks a day and some tug plus chew toys isn't really enough for most young GSDs. You need to be doing more active exercising, as Maggie suggested. Expose her to new situations, let her run around on her own in new environments (if her recall isn't trustworthy yet, dog parks are a great answer, as is work on a 30-foot lead in an open field), give her things to think about. Tire her out physically and give her plenty of mental stimulation, then ignore the hair pulling on top of that and I bet it will disappear pretty quickly.