Maternity leave

When do you take maternity leave/ plan to take leave? I'm 38 + weeks and I'm considering not returning once I hit 39 weeks this Saturday. I feel very irresponsible about this decision bc I know there's always a chance of staying pregnant until 42 wks and I won't get to spend that time with baby. But I'm very uncomfortable standing upright already. I'm 1 cm dialated & 50% effaced and I've been having cramping/ low back pain. I just want to make sure I get in at least a week of personal time for myself before baby arrives (I haven't set up crib or stroller yet, I've been working so full time). But at the same time I know mommas on here have said that since they've began maternity leave, the pregnancy begins to inch by really slowly. What do you guys think?