"baby changes everything"

my boyfriend and i have been together for 2 years, but we've been best friends for 5-6 years. we've been talking about marriage since before i even got pregnant and since falling pregnant everyone keeps saying how much a baby changes relationships and how we should hold of on getting married because babies make everything different. I am soo confident that our relationship can handle a baby, if anything we have grown closer since being pregnant and i can only imagine once we meet our daughter that it will only get better. so my question is, is it true that babies change your relationship entirely, for the better or worse? please comment