i also vote no. the last time we were at SW was for my oldest son's 3rd birthday. it was february and INSANELY HOT. although i really LOVE seeing the marine animals, it was very, very uncomfortable.
also, small kids get really frightened by the big splashes during the shamu show. we went to the one in ohio in '95 because my dd who was 3 at the time was completely obsessed with killer whales. stood in line for an hour and a half to get the best seats in the stadium, and what does she do?.....the first splash from the whale and she completely panics and dives under the bench we're sitting on!! gets a huge scratch on her back from the metal bench, and is scared to death for the rest of the show.
when we took ds to SW for his 3rd b-day, we sat farther back, but he still completely freaked out and started crying when we got splashed by shamu. on both visits, my kids were not the only small kids who were screaming after the first big splash, either. just to give some perspective, my same son, at the same age, was more than happy to ride things like POTC, haunted mansion, and even matterhorn at DL.
my recollection of SW is that it feels like there is NO shade ANYWHERE.
also, your dd is really too little to enjoy the kid's play area at SW, because so many parents let their kids run totally wild and she'd likely get run into and even knocked down by bigger kids whose parents aren't paying attention to what they're doing.
DL is way more enjoyable than SW, even for small kids. at least, that has been my experience (4 kids, ages 4-17).