Does crib mattress height matter if it’s lower?

Sorry I couldn’t figure out a better way to word this question lol but we set up the crib before my daughter was born with the intention of keeping her in our room with us until 6 months so it’s lowered to be safe if she can sit up. She’s only 7 weeks now but we want to start letting her take naps in the crib. My question is: is there any safety reason that it needs to be at the highest height since she’s still a newborn or is it fine to keep it lowered? Just really don’t wanna go through the trouble of raising the mattress up if we don’t have to.