What age did you actively try to avoid naps close to bedtime? Also, how many hours before bedtime would you let the last nap end?

We do the obvious thing and let our 14 week old LO sleep whenever she shows us she's tired (usually she can last 65-75 minutes awake) and her last nap ends about an hour before bedtime. I always assumed there would come a time that we need to be cautious of the timing though.

Lately she's been having some super long naps. She usually takes five or six 40 minute naps a day (major catnapper!). The last nap is usually from 6:00-6:45, but the past week she's taken some two hour naps during that time. Yesterday and today she slept from 5:30-7:45, and she only woke up because something woke her. We normally put her down for bed around 8:00, so the late nap makes me nervous for night time, but she obviously wants/needs some sleep. I wonder if this is her moving her bedtime super early or just going through a growth spurt. Either way I'm happy for the long naps, but did anyone else experience this?