Absolutely include the babysitting. It is "work."

Everybody's got to start somewhere. At this point in your life, your resume will be mostly a record of education and skills. List computer programs that you are proficient in, too - whether or not you have taken classes in them. Emphasize your strengths and abilities.

Alas, "upstanding member of Pet Talk" doesn't go on resumes, but hey - depending on what you're applying for ... just kiddin'