Our kids were 13 months and 2 years during their first trip to WDW, however, my daughter was seven months old and her brother was -5 months when we went to DLP after a baltic cruise on the Magic.
At those young ages, the trips aren't really for the kids. They are for everyone else. While it is still fun to see how a baby or toddler reacts to a huge mouse or a princess, they'll never remember it.