Well, I too was told with my other children to start solids at 4 months. My eldest had projectile reflux with every feed,,,, was medicated, and as he was also 12 weeks early,,,, doctors were desperate to get some weight on him . So at 16 weeks old (yep, you got it,, 4 weeks corrected age!!) I was ordered to start farex. I shudder now to remember back at how hard it was to feed him that at such a tiny age.
My next 2 were also recommended at 4 months,,,,but I started them at 5 and 6 months old, when they were hollering down the house for it.
With Griffen however, I tired to wait till the magic 6 months,,, but he was so underweight,and losing weight that I was advised by the health nurse to start one meal a day at 5.5 months. He was however displaying an eczema rash on his face before then, and still has it.
If I had not been advised to feed him at 5.5 months though,,, looking back though,,, he needed it. I did not have anywhere enough milk, and he was starving,, screaming all the time.