It's hard when a professional gives advice labs but I have to agree with CMOT, around 6 months is the guideline so your HV has given you incorrect advice.
Based on what you have told us, your DC doesn't seem ready for food.
The guidelines changed from 4 months to 6 months (can't remember when, approx 5 years ago?) but the baby food manufacturers are still allowed to market to 4 month olds onwards ie baby rice, purée jars etc. Research suggests that a baby's gut isn't ready for foods until 6 months, hence why the world health organization (WHO) recommend exclusively breastfeeding for 6 months. With formula feeding, they also recommend this for 6 months.
What signs do you think your baby is showing (to be ready to be weaned)?
The signs I looked for included:
Siting up unaided
Grabbing food off your plate
When eating food, pushing it around their mouth (and out) ie developing their tongue thrust
Interested in the food they grab (not just straight to mouth...for example, most toys and remote controls
go straight to my dd's mouth at 4 months because that's what babies do at 6.5 months, she'd look at the food in her hand, inspect it even, before putting it in her mouth.
(has anyone else got any other signs, I'm sleep deprived today and may have missed one?
)
Maybe have another chat with your HV and mention baby led weaning, see if she knows about it / advocates it.