The question is in the details :)

She is supposed to be in pre-k

It depends on her birthday, and also on the rules of the school she goes to, but most kids start kindergarten at 5+.

That is true, but I was 4 turning 5 when I entered kindergarten. My birthday is in October. Although she should be in pre-k.

There is no way to answer this without knowing your general locale. Laws vary by area. Your school district may not even have a Pre-K program or it might not be mandatory.

As Joy said, most children start in the year they turn 5. But the best place to get this answer is from your local school district.

Why are you concerned with this?

The age for one state ( if US) is not the same as other US states. A call to the local school board will tell you the local answer