The first day of school can be a confusing time for students and administrators, but even more so for rookie teachers straight out of college. That first year is when many decide whether they are cut out for a teaching career. According to the National Education Association, nearly half of all teachers quit the profession within the first five years. In this series, “Ms. Miller’s Class, Established 2013,” WYPR’s Gwendolyn Glenn occasionally checks in with Danielle Miller, a first-year, seventh-grade science teacher at Holabird Middle School in Baltimore County.