Start in June and just enjoy the process. I'm a teacher too and wanted to get pregnant over the summer to have a March/April baby but it surprisingly took us a lot longer than anticipated. Just check with your union rep if it does take a bit longer because a coworker had her baby in July and she was told that the summer is her "own time" and therefore she was not entitled to a full maternity leave.. She only got 6 weeks off from teaching so her baby was only 2 months when she had to go back to work.