Are you trying to get her to sleep through the night or do you just want to understand what's normal at this stage?
Waking up every 3 hours at 4 months is completely physiological - her little stomach is tiny and milk gets digested pretty fast. It's not that something's wrong, it's that she still needs to eat frequently. What happens with your friends is there's a lot of myth floating around - some exaggerate, others get lucky, and some put their babies to sleep longer than recommended before it's time. Your daughter is perfectly fine where she's at.
Now, here's what nobody mentions: it's not a good idea to push for her to sleep through the night too early. At 4 months sleeping 6-7 hours straight would be unusual, and babies need to eat often. After 5-6 months a lot of them naturally start needing fewer night feedings, but that really depends on each baby. The only thing you can try is making sure she eats well during the day - babies who are satisfied during the day tend to sleep better at night, but it's not guaranteed. If you're breastfeeding, you'll notice she gets faster and more efficient at it over time. If she's on formula, you can offer her a bit more in her last bottle before bed, but don't get obsessed about it.
What matters is that your daughter is doing well, she's growing, and these wake-ups are what you'd expect. In a couple of months it's going to change on its own 🌱