Hey! Your 7th month officially starts at week 27. You are finally entering the third trimester, so exciting! Don't stress too much about exact days, just enjoy this phase.
My doctor told me that week 27 marks the beginning of the 7th month. Many sources say 28 weeks, but medically 27 weeks completed means you have started your 7th month.
According to my tracker app, 26 weeks and 5 days completes your 6th month, so week 27 is the official start of month 7. The apps are so helpful to track these tiny details daily.