Erm, isn't 10 hours a day approximately one full-time job?
If she's, say, taken a six-month sabbatical to learn to make websites, this seems eminently reasonable and doable without speculation about mental illness.
Shrug. Maybe it depends on whom you hang out with. Personally I spend a lot of time with successful entrepreneur and creative types. This sort of focus and commitment, whilst it's definitely laudable, isn't abnormal amongst that crowd.
...and your existing bills and how you are able to pay for them.
I've got a 1 hour commute each direction, and an 8 hour a day, soul-sucking, brain-energy-sucking job. (HN is sanity retention medicine for me.) By the time I get home in the evening, fix dinner for the kids and me, eat, catch up with the family, etc. I don't have a lot of time or energy for anything else.
Also doing it out of a paid-for shared workspace. I mean, I love the stuff she's doing, it makes sense that she'd be able to do it working full time, but she must be independently wealthy to be able to afford it.
I know nothing about Jennifer or her lifestyle. But it is not that hard for a young, single person whose main activity is being productive to save up 6 months of living expenses.
Use of shared desks costs like $200 a month at places like Citizen Space, so it's not like that's a bank breaker.
If she had a family it would make less sense. If she were living a 'baller' lifestyle, drinking and partying every weekend, it would make less sense. But if she's an unattached workaholic, her life probably costs very little and no independent wealth is required.
I know a fair number of people who have retrained at University for another career, for example. Most of them weren't independently wealthy - they'd just saved up enough to be able to afford to go to university for a year.
While it is far from a definitive diagnosis, it isn't 'normal'.
Without a doubt it is ambitious, and her progress thus far impressive!
If only we all had 10 hours a day for a full 6 month period to spend pursuing ambitious goals ...