6 week old baby sleeping through the night??

My baby girl sleeps 7 hours+ at night. She went to sleep at 8pm yesterday and I had to wake her up at 3am to eat. She nursed on both sides and now is back asleep.

I hate to even say it, but should I be concerned about how much she sleeps at night? She has alert wakefulness during the day, with little naps and is rarely fussy. This is my first baby and I just didn't expect to get this much sleep at night by 6 weeks…