go-getter
A very active, determined person who works hard for goals.
A go-getter is someone who pursues goals with energy, determination, and initiative. Go-getters don't wait around for opportunities to find them: they actively seek out chances to learn, achieve, and succeed.
Think of the student who completes assignments and also asks the teacher for extra challenges, or the kid who sees a problem in their neighborhood and organizes friends to help solve it. Go-getters take action. When a go-getter wants to learn guitar, they find a teacher, practice daily, and maybe even start a band. When they're interested in robotics, they join the club, watch tutorials, and build projects at home.
The term captures drive and initiative to make things happen. A go-getter sees what needs to be done and does it without being asked. They're not waiting for permission or for someone else to lead the way.
It applies to anyone with that combination of ambition and action, whether they're starting a lemonade stand, training for a marathon, or mastering a new skill.