I don't think his age is necessary a problem, but I think that you are unlikely to get value for money at that price until he is older - If he is keen, I would shop around and see what your local council, or lower order football teams offer as they will tend to be cheaper and would certainly be suitable for his age. I think that our council classes cost about �30 for ten weeks and our local football club is a similar cost.
You will also find that he is likely to learn just as much in terms of skills at the moment from playing with his Dad/uncles etc as this is fun for him and is on a 121 basis and a class would be bigger.
If you are looking at it from a fun point of view then that is something else again, but it does seem a bit expensive.
I think an older child would get a lot more benefit from professional coaching.