Just send her to Preschool... when she is the age you are thinking about.
When I had my 2nd child, my daughter started Preschool. She was about 3.5 years old. And she WANTED to go to preschool, although she had been home with me and I am a SAHM.
A child, will naturally reach a certain juncture, of either needing to go to Preschool or wanting to go. Due to their age phase. And to socialize more with same age peers and for more stimulation and activity. So keep your eye out for that.
For me, I KNEW my daughter needed Preschool and then she started telling us she wanted to go. Even though she had been home with me and was very attached to me. But she adjusted like a champ. And loved going.
School, is about "academics" learning and about socialization learning and development of emotions and coping skills, and getting used to following direction and being in a group of kids. So it is not only, about academics.
Per naps: well my daughter always napped too. So did my son. And they both napped still, even if going to Preschool. They simply napped AFTER preschool. They attended Preschool part-time for half days. So, they still napped once they got home.
Per potty training: some Preschools accept kids in diapers, and will "train" them. Some do not. So... you need to do your research and do site visits and talk with each one, and then decide which one is best for your daughter. Some Preschools are very rigid and formal. Some are more nurturing and flexible. So, you need to discern which style, is best suited for your child. And which one your child likes.
"Maturity"... is something different than academic knowledge. Some kids are very ahead academically per their age. BUT then their maturity and socialization skills, is not ahead. So, Preschool is still very applicable for them to learn this.
2) Then, thinking ahead to Kindergarten:
In my State, Kindergarten is full days. Kids adjust just fine. Especially so if the child went to a Preschool, first.
In my State, Kindergarten is for 5 years olds or turning 5, or there are some that are turning 6.
KEEP in mind... that in some States, if a child is already 6 years old and entering school, they may place that child into 1st Grade. So, you need to ask the school, about their age placement. That is how it is in my State. But the parent, can request that their child be in Kindergarten even if they are already 6 years old.
Or... there are schools with a Pre-K class. These are for late born children. It is like Kindergarten, but for late born kids.
Then, you need to consider your child's size. Meaning, some kids are tall for their age. So if they are entering Kindergarten at 6 years old, they may be the biggest one in class. And if that bothers you/the child or not.
Lots of factors to consider.
And yes, as the Mom, you need to be ready to send your child to Preschool or school, as you see fit... or as you recognize your child's needs for leaving the nest.