Hi! I can't imagine why she would have thought twice about your measurement. Usually we use how many weeks you are as a guideline to how many cm you should be, but not everyone is exactly 36cm at 36 weeks. Being .5 off is totally a non-issue. Plus or minus 3-4 cm is still within normal limits, especially if you had good interval growth (fundus grew from one appt to the next). I have always measured small, really small for dates. Usually 3-4cm under, for example, I am 35 weeks now and am measuring 32. But I was 28.5 last visit, so it shows the baby is growing, and therefore not concerning. I would totally not worry about it, especially with only .5 of a cm!
Midwife mama to DD1 (4.5) and DD2 (1.5)