Short naps!

My baby will be 5 months next week and she is a great sleeper. Puts herself to sleep for all naps and bedtime and sleeps through the night from 8pm to 6:30/7:00 am BUT she will only take 30-45 minute naps. I will usually go and rock her back to sleep and she will nap for at least another hour which tells me she’s still tired after those 30/45 minutes. Idk if I should stop rocking her back and hope that she figures out how to nap longer or what. Any one else have this issue?!?