"I feel that I've grown up a little bit and I'm actually ready to settle down"

This quote by Peter Steele suggests that he has actually gone through a duration of personal growth and development, and is now all set to take the next action in his life. It indicates that he has reached a point in his life where he is all set to dedicate to something more long-lasting and stable. This could mean that he is prepared to start a household, or to settle into a more permanent job or profession. It could also imply that he is ready to make a more severe dedication to a romantic partner. Whatever the case, this quote recommends that Peter Steele has actually reached a point in his life where he is prepared to take the next action and settle.