If the school your son is offered is far enough away, he qualifies for free transport from the Local Authority. Many parents are happy with that, but others aren't comfortable with the transport offered. Transport is something to consider when deciding whether to accept the school you are offered.
Once the council has offered a school, they have fulfilled their responsibility. You then have a number of options.
You can accept or decline the school. If you decline it, the council has no obligation to offer you a different school so you would have to be prepared to make your own arrangements if you can't get him into your preferred school. Your son isn't legally required to be educated at all until the term after his fifth birthday, which in his case would be the September after he is five. The year he is four, you can send him to preschool instead of school if you prefer; the government funds a half-time place there. In theory the preschool curriculum for four year olds is the same as the school curriculum for four year olds. You could send him to a private school or home educate. Home education is very straightforward - you can use whatever methods seem best to you - and some parents use it as a way of delaying school start to a later age or waiting for a better school. Whenever he joins state school, he will go into a class with his "age peers": kids in English and Welsh state schools are rarely "held back" with younger children.
Whether or not you have accepted the school, you can join a waiting list in hopes something better will come up. You can also appeal for the school you prefer.
In the first (Reception) year of school, you can keep hold of the place your son is offered without risk of losing it, but defer his start. This is age-linked. In your son's case, the latest he can start without risk of losing the place is the summer term (April). Some people do that as a way of buying time while waiting to see if they can get their child into their preferred school. Best case scenario, he gets a place at a better school and starts during the year, not having had to settle in at one school and be uprooted to another. Worst case, nothing better comes up and he starts in April at the school he was originally offered - but at least you haven't lost that place too and ended up stuck with an even less desirable school.