When I went to kindergarten, and when my mom taught, we had quiet/nap time. They did away with that by the time my kids went through. Some kids still need it. Mine would come home and konk out at the end of the day, especially as they were getting used to school. I used to adjust their bedtime.
One of mine, to this day (tween) still passes out in the car - nap - when we go places. Some kids need naps. Some adults do.
If I read a book in the afternoons? I will crash. It's like if I stop and rest, I'll nap. I have friends who are the same. I don't think it takes much for most people to have an afternoon nap, if given the chance. I think a lot of little kids could - it's just that we expect them not to - once they start school.
If she starts school and still needs one, a little cat nap (even 20 minutes) when home worked for mine until they adjusted. It didn't interfere with bedtime. I found otherwise they were really out of sorts.
ETA: I saw your So What Happened. What time does she go to bed? My kid who naps in car has a later bedtime than my older kids. I just let her stay up later (I was more lax about bedtimes). You could move her bedtime up. My oldest kids went to bed very early - especially at that age. It seemed super early, compared to my younger kids. I just did because they needed their sleep and I wanted them well rested for school (we did before/after school programs when I had a busy career). They did not nap, but as I said, right after dinner, they played for brief while, then it was bath, routine and bed.
So if you need to, you could adjust bed time and start cutting back on nap if you're concerned. If you're worried she won't be able to get through day by time school starts and she is still napping - that's maybe the approach I would take. So long as she gets the sleep she needs? Doesn't matter how.