Pink is supposed to be a calming color.
Certain colors will affect activity. Try research it online.
A good idea might be to paint it in a way that will grow with the child... otherwise you will need to redecorate at different ages.
So use accessories to decorate, which can be changed out quickly and more cheaply... pillows, lamp shades, area rugs etc. Walmart has lots of bedroom decorations for kids. Reasonably priced.
Use a latex paint... easier clean up with just water, easy to apply, and if dirty can be wiped clean. Use a finish that is at least semi-gloss... because "matte" paint will stain and attract dirt and it is hard to clean.
You can also put up alphabet or number type posters etc., and simply by "seeing" it everyday, a toddler will subconsciously "learn" the alphabet etc. Just an idea.
All the best,
Susan