It's actually not healthy for a baby to sleep through the night, so I would be perfectly fine with her waking to eat at 3am. It sounds like she is still sleeping well.
When my youngest was that age, what I did was (and we co-slept too!) nurse her right when she would start to squirm, not waiting a moment for her to wake further. Then, right after nursing, I would change her diaper, because they sleep better dry. She slept through the diaper change.
They do need calories, etc through the night at this age. It isn't good for a baby to go several hours without eating, and it's really a modern American thing to expect an infant to sleep all night. It's not normal at all, and increases their chances of dying from sids! It is completely normal for all humans to partially wake all night long. While an infant's brain is developing, they don't go into the deep sleep stages like we do. So, when people insist on your baby learning to sleep all night, I would ignore them. They'll sleep through the night when they are ready.
I would follow her lead and enjoy it while you can.