C.M.
R.,
You should start brushing their teeth as soon as the buds pop up, but better late then never...according to my kids dentist parents should brush kids teeth for them I sing the abc song twice and try to hit every tooth. Also they make non flouride toothpaste-there is enough in water and kids should be able to spit before going to flouride. My oldest insisted on brushing his own teeth, but it was not good enough-he had a cavity, so I recommend doing it for them from the get go...Good Luck.
By the way you are not a slacker. Oh, you may want to let her pick out a toothbrush-it will make her feel like part of the process.
C.