I actually don't agree it doesn't matter and they are only small fur a short time.
The OP has never said she was pushing him to learn she said that child wanted to learn.
I have a child like that has self taught science at Alevel when he was in primary.
I've never done ANY extra work with him just gave him the opportunity to see/watch/read things that I though he would enjoy.
The thing is I could also have said 'oh he is only a child. Let's leave him play and enjoy himself. Why giving him books about chemistry and the structure of atoms'
What would have happened is that I would have stopped his enquiring mind, I would squashed his curiosity because let's face it, what another child would have found interesting, he is finding boring....
It is essential to provide opportunities and interest at the level of the child. It is also essential not to forget they are individuals and they need to develop their emotional intelligence, their social skills etc.
It's not about going one OR the other they are not incompatible as some pp seem to think. It's totally possible to learn 2,3, 5 years above your age AND play AND have friends AND do some sports.
No parent should ever feel uneasy because they are giving to their child what suits them. Whether it's much more complex than you expect it much more simple than you expect.
And yes that also means that some children will LOVE the very academic work of learning phonics. Even if most don't or if we, as adults, have very bad memories of it
But by not giving them opportunities to learn what they enjoy, you are actually stopping these children to learn that learning is fun and enjoyable. You are stopping them from growing up and learning at their own pace. If that is what is suitable for most children, the ones that are struggling etc why is it not suitable for those who are ahead?
As for not making a f* difference when they are older, I would say that how well you are doing is linked with a myriad of different things, not just how intelligent you are. So not expecting your DC to be the next Einstein is probably my a good idea. But saying they won't do better than most Is wrong too. They clearly have the abilities for a start. Why acting as if being bright makes no difference at all?