Your age is fine in terms of wanting a baby, but I would be mindful about how difficult it may be to get pregnant and the complications of how you being older may affect the health of the baby.
Also, think about the impact it will have on your other children.
In my opinion your husband is far too told. As another poster said, if having children was so important to him then how come at the age of 57 he hasn’t already done it?
I have a 5 year old and a 2 year old and my parents who are both just about to turn 60 can cope with their excitement for about a day before they are then ready to hand them back.
My children exhaust me and I’m only 36!
Do you really think that at the age he is, your DH will be able cope with a young child? And then all the added stresses as the child gets older? Especially if they do have addition medical needs due to the ages of you both?
When me and my DH were TTC our second baby he said that if we hadn’t conceived by the time he was 35 then we would stop as in his eyes, that is the cut off age for becoming a new parent.
Admittedly I did think that was a very extreme view, but I do think 58 is too old to become a new dad, and that’s assuming you get pregnant quickly.
I think you both need to really, really think about the possible implications if you choose to go ahead.