Waking baby to feed?? FTM

Mariah • Follower of Christ | Wife | Mother of 2

My baby girl is 18 days old she’s gained her birth weight since she was 5 days old, I usually wake her up to feed her if she sleeps more than 3 hours during the day but at night I let her sleep and let her wake up on her own if she gets hungry.. she usually sleeps for 5-6 hours during the night but my question is.. is it alright for me to let her sleep already or should I wake her to eat??