start solids when 6 month completed or when 6th month begins?

Hello, I am a little confused about the toming of starting solids. Everywhere it says that you should wait till 6 months before starting solids. My baby will complete 5 months and start the 6th month this week. Should all D's bye started at beginning or end of 6th month.

I am considering starting baby led weaning and maybe oatmeal. Baby can hold head up steadily, not sure about tongue thrust reflex gone or not. Baby feeds every 2-3 hrs and wakes up every 3 hrs every night.

Thanks,
Cooks