I disagree with those saying that as a doctor work is your life. That is certainly true as a junior doctor which is when I had least spare time but once you reach consultant/GP level there is more of an option to work part time and because you aren't continually studying/ working your way up/ moving around things settle down. I think this is where mature students can have a hard time if they are trying to combine being a med student/ junior doc with being a parent and attentive partner.
You have to like problem solving, people, be comfortable with risk, thick skinned and able to cope with stress.
It's not a good career for those who like science but are very anxious. Some of the thick skinned stuff develops over time. It is a people career not a science career though primarily, even in specialties like neurology and surgery dealing with patients' personalities, health beliefs and expectations is a major part of the job.