11 week old sleeping 8 hours?

For the last 3 nights my daughter has been sleeping from 9pm to 5 am. She sleeps in a co-sleeper next to my bed and I wake up a few times to check on her throughout the night. She sleeps very soundly all night. Is this okay? Also, since she has been doing this she has been eating every 3 hours instead of every 4 during the day. I guess that is normal since she sleeps so long at night?