Hi L.,
Children are sponges, and young girls are more mature then young boys. Also, individual children develop at different rates. The rate at which children develop does not necessarily determine their potential to achieve later in life.
Many young boys who are still in diapers at 3 1/2 will become tommorrows great scientists, lawyers, politicians, writers, musicians etc.
I cannot tell you if your daughter is "gifted" I suppose that depends on how you define "gifted". If she is thriving, happy, engaged and your finances can afford it than I say continue to provide her with enrichment classes that she enjoys.
You could always consider having her professionally evaluated if you think she would be bored in a classroom with other children her age. But, remember, you have to balance her intellect with her maturity.
Even the greatest child prodigies are still children, let her enjoy this short time of innocence. What most people, regardless of intellect, desire is acceptance and good friends these blessings are available to all.
God Bless,
J.