EVERYTHING she knows about her world, people, animals, clothes, toys, language, etc, she has, amazingly, learnt in less than three years!
What new stuff have you YOU learnt in the past three years?
Every new experience she is exposed to will be making synaptic connections in her brain, that will help to build her intelligence, memory, personality and more:
www.human-memory.net/brain_neurons.html
So, yes, do plenty of activities and games with her, talk and read to and with her, as much as possible, but please don't make learning to read, write, count, draw or anything else, a task that she needs to achieve.
A fun way to help her develop, is through music; if you can afford it, a Keyboard (61 full-size keys) will allow her to explore sounds, rhythms, sound-patterns, tunes etc. (By two our DS was playing on our Yamaha organ, and by five was reading simple music and making up his own tunes.)