1 nap, 2 naps, 3 naps, 4!

Hello,

I have a 15 month old and I don’t know if she is ready for 1 nap yet. Her bedtime is anywhere between 10:30 and midnight. She sleeps until about 8am. She wakes up and then she goes back to sleep around 10:30am to about 12:30pm. She then takes another nap anywhere between 5pm and 6:30pm. I only let her sleep for no more than an hour. Then she goes to bed 5 to 5.5 hours after her last nap, which like I said could be anywhere between 10:30 and midnight. She does really good with 2 naps during the day. She sleeps well at night with 2 naps. But sometimes (mostly weekends because her dad is off so we sleep in) she wakes up at 10. When she wakes up at 10am, I only give her 1 nap around 3, and let her sleep 2 to 2.5 hours. Then she goes to bed 5 hours after. So I don’t know if she’s ready for 1 nap or not bcuz she still does really good with 2 naps. She doesn’t fight when she naps, and the longest it takes her to fall asleep is 20 mins. Do I continue her 2 naps? Or just wean her to 1 nap bcuz of her age? Also, is her 1st nap just a continuation of her night sleep? Help! I’m soooo confused. Thanks all!