Apple is a chocking hazard, especially at such a young age. Babies gums are very sharp so she could bite some off and it could get stuck. I'd really suggest you stop.
I personally wouldn't introduce it, I'll be waiting for all the signs and milestones. This might be at 6 months, might be later My baby watches me drink or eat and sometimes reaches out but she's in a development phase, they also explore by putting things in their mouth - not for eating. I know there's some links to gastro issues and early weaning. She's increasingly trying to eat my clothes or hands as I try and change her too 😂
Would definitely say hold off as its too early to be introducing anything other than milk into your baby's diet. Also a note, my HV advised when you are starting weaning go for vegetables first as babies prefer fruits since they're sweeter like their milk. And you can make it really hard to introduce the more savory and bitter flavours if you introduce fruit first
Your baby does not need food or to be sucking apples until they are ready to wean which is around 6 months of age unless advised by a dietician/paediatrician.