Homeschooling question for Amy Dingman Teen Catalyst

I sent a homeschooling question to Amy Dingman, from A Farmish Kind of Life podcast and website. Amy has lots of years of homeschooling experience, having homeschooled several of her own children.
The question I asked is, where parents start who are new to homeschooling and want to maintain the necessary studies, while also giving their teens what they need to keep their mind activated and interested in what they are learning.
Where is the dividing line between letting them jump from topic to topic exploring everything that happens to capture their attention, and keeping them focused and moving forward on the things that will help them create a life they actually enjoy living?