I knew a girl who worked really hard to get into Medicine. She did a degree in Biomedical Science, worked for a few years then did a Foundation Year and started medical school in her late 20’s. She got pregnant in 2nd year and left at the end of the year to have her first baby. But she ended up having a second child too and never returned to finish her degree.
My point being that your priorities can easily change when you bring children into the picture. If you’re planning to have a child during medical school, you’ll have to work much harder to stay focused on keeping up with the workload and passing your exams as well as spending time with your child. You seem to have a good support network but will it be enough to help you manage the work?
Personally I would suggest you wait until you graduate before having children. Medicine is a full time commitment and your mind needs to be on the work pretty much permanently all throughout the course. There’s no room for distractions. At least when you graduate and start work, the opportunities for working part time are there (not possible to do PT study for medical school). But if you’re really determined to have children sooner rather than later, within the first 2 years is best, i.e. when you have uni-based teaching 9 to 5 rather than travelling around everywhere for clinical attachments.