My DD is 15mo so not quite the same, but she naps for about 45 minutes after lunch when she's at nursery. However, on days she's at home she naps for anything up to about 4 hours..so I'd say if she's tired, put her down for a nap!
My little girl is very active and at the moment her one nap is 1pm and is normally 1 hr 15 or 1 hr 30min in length.
She then has her bath and is asleep by 6:45pm. She then wakes around 6am.
Recently she sometimes dozes off in the car around 11:30am as so busy so this can disrupt her post lunch nap.
Just wondered if she should have more daytime sleep now she is busier and whether her nap should be earlier in your opinion? If its earlier then would you recommend lunch beforehand like what she is used to?