I agree with you, but a baby can’t read a ballot or pull a lever

I absolutely get the sentiment, but with arguments like these i always end up running into hypocrisy and double standards. There are plenty of illiterate adults and we are rightfully allowing them to vote, so do the blind. Paralyzed people are also voting despite them not being physically able to move a lever. As you said, there should always be help available.

In practice i doubt many babies will articulate a desire to vote and the number of extremely young children will also be limited. So to me if a 6 year old comes up and says "i want to vote" i say let him, he certainly is affected by the consequences of the elections regardless.

let anyone who is able to register go to the polls.

I would note that depending on the implementation this can also be a unneccesary hurdle and be abused as seen in the US.

As an inherent right it really should be as automatic as practial limits allow it to be (some sort of register is ofc needed to prevent voting multiple times).

Here in Germany for example it's simply tied to your registered primary residence, which means that only people without such have to actively seek out registration wherever they live.

I would be concerned about a certain type of person trying to make as many little voters as they can crank out, but I suppose some people do that anyway and just wait until they turn 18.

And that's the slippery slope: Who gets to decide that "certain type of person"?

To go with your example of the number of children: I think statistically poor people have more than the rich. Is that what we want to fight? Also who is to say that children vote the same as their parents?