Hey there, when I came here it took me a while to sift through the many many bad dance school websites until I found one that had actual info (hello, a schedule!?!?) that was useful.
SO. For your daughter, she MIGHT be a little young. Most classes for the little ones (pre-ballet, fun movement classes) start from 4 or 5 yrs. Not saying that is true here, but it is a possibility!
Anyway, you just might have to go through this list until you find what you are looking for in the area you are looking for:
http://www.todoar.com.ar/r/Capital/Escuelas-de-danza/
The Fundacion Julio Bocca does offer 'clasico para ninos' at their San Ysidro studios. But that is kinda far from Palermo.
http://www.fundacionjuliobocca.org.ar/system/contenido.php?id_cat=40
Their downtown studio is good for adults, but not for the little ones.
I take class from 2 different teachers at Domus in San Telmo, Rita Caride & Nadia Freedom. Perhaps contact the studio to see if they give lessons to children elsewhere? Or just ask them if they know where to find what you are looking for.
They are super nice and energetic :O)
http://www.domusdanza.com.ar/index.html
Heck if you have a studio space I will give her a pre-dance lesson. They are more about playing, hearing music, learning to mimic, it is cute.