Girls learn so much faster than most boys usually. My daughter was talking in complete sentences at 18 months. My 3 other sons, not so much. LOL
She is now 4 and almost finished with kindergarten. We decided to homeschool our kids, so they they would never be slowed down from learning at the pace they needed. She's writing and spelling words like "avocado". We just encourage her and she takes it and runs with it. We never push her, but allow her to lead the way.
When she was 2, we were at a park and the kids were playing hide 'n seek. This one mom had to count for her 3 year old son because, "he's just 3 and doesn't know his numbers yet." That's ok. My daughter looked incensed and told me, "Mom, I'm 2 and I can count to 10 in English AND Spanish."
Our 1st son was NOT homeschooled in kindergarten, but started kindergarten at 4. He was so bored and wanted more, even though he was in a dual immersion at San Juan Elementary and learned to read and write Spanish before English. This helped his reading tremendously. He just turned 10 and reads at a high school level. He finished all 7 of the Harry Potter books when he was 9 - and read them in 3 weeks on top of all the other work/reading he does. We pulled him out of school after kindergarten when HE asked us to homeschool him. My husband and I weren't even sure if we knew how to do this...but it has turned out gloriously.
Keep encouraging her and let HER lead you. Once they get bored, that's when trouble strikes.