That is an INSANE amount unless you're a daily 15km runner or do a very active job (e.g. nursing, warehouse work, landscaping, etc)!
I can do 20k steps...if it's a day I either do a 15km run, or a 7-8km run on my office days (3km walking commute).
Even if she's walking a fairly brisk pace (11 min/km), that's 2 hours 45 mins of walking. Which doesn't sound like too long, but since she works from home and drives everywhere, that's basically a >2.5hr workout every day. Which wouldn't include her other workouts.