Coding as a child often makes you a better junior developer. It very rarely makes you anything but a junior developer, your first few years full time at it.
This is very true. I had my first full time internship last summer and although I wouldn't say I was unprepared, it opened my eyes to all the things I don't know. Code reviews take some getting used to when you're coming from a purely academic world. From reading hacker news I knew there would be blindspots in my education. It felt good filling in some of the blanks.