The first obvious approach would be to become an elementary school teacher. Not only will you be working with kids, but you'll be working with them at a point where your influence and counseling will be most needed and effective. Remember that a teacher is one of the most significant influences on childhood development and later success in life. Teachers are role models, and good ones can be precious. Adult influence in the molding of a young person's future self, attitude toward the world and ability to take on challenges and be both successful and resilient is often sorely lacking in a person's development. I believe that adding more positive adult influence on a child -- not only parents, family members, grandparents and friends -- will help alleviate much of our problems with young adult behavior and happiness. I've been extremely touched and gratified when a former student tells me what effect I've had on their lives and how earnest they were in sharing this with me. There's nothing quite like hearing a person tell you that their success was due to "you changing my life".
A career as a child life specialist might interest to you. A child life specialist works with children who are in the hospital. They help the patient and their families cope with the stress and anxiety of being in the hospital, prepare kids for tests or procedures (like MRI scans or surgeries), and help with non-medical pain management. They provide activities and organize special events like birthday or holiday parties for the kids. Child life gives you the opportunity to work with kids of all ages (from birth to early 20's, depending on the hospital) and of all developmental abilities. They make a huge impact on the patient experience.
To become a Child Life Specialist you'll need at least a Bachelor's degree in Child Life or a number of other areas of study (psychology, social work, child development, etc), and there are Masters degree programs as well.
Rachel recommends the following next steps: