Joan Nguyen has spent her career being the boss: In her early 20s, she built and ran MeriEducation, a global test prep and educational consulting company, that she launched with just $3,000 to start. In 2019, she co-founded and became CEO of Bumo, an app that connects parents with child-care facilities in their area. The idea to provide on-demand, flexible child care came from her own needs: When Nguyen found out she was pregnant with her daughter eight years ago, she immediately got on the waitlist for a day care.