Should I limit the nap time for my 3 month old who is waking at 4/5am
At this age you're probably still having around 4-5 naps a day, depending how long each nap is.
Lots of baby's at this age have short naps (45 mins) so need more naps.
If your baby is having more than 4-5 hours of daytime sleep you might want to look at how much they're having. But normally at this young age unless there is some day/night confusion I wouldn't limit daytime sleep.
Early waking often comes from over tiredness so also check your little one isn't awake too long between naps (60-90 mins again depending on nap lengths, short naps = shorter windows)
This could also depend on night feeds and if your baby is waking for a feed at this time. Which is also very normal at this age.
If you are struggling with early waking I have a whole workshop covering this!