The internal part can be replaced too.

The gain you get from implanting as soon as possible is massive compared to waiting it off. No one truly considering it should be waiting and instead actually pushing for an implant as soon as possible.

For our son, in the UK in 2019, they asked us to wait until our son was one year old. We insisted to have him implanted as soon as possible and us being ready to do it at 6 months (possible already in US). We managed to do at 7 months only switching surgeon to a much younger and keen surgeon that was pushing to lower the implantable age in children on the back of the massive benefits gained and very similar complication rate as close age brackets.

Our son is currently in mainstream school and doing brilliantly.