Looking for reassurance

Hi, my little girl is 5 months and never really napped she use to probably have 20-45 mins every nap (4 times a day) now she's been having 2/2.5 hour naps! I don't think i need to be concerned as she's feeding 8oz x 4 and having plenty wet and dirty nappies. It's just a bit odd for us cause she's never been a great napper but always slept through the night.