I second the idea of joining the committee for a year or so, even if you ultimately plan to be an ASM. Particularly if the troop your son joins isn't absolutely desparate to get another ASM signed up (they have sufficient help in this area for now).
In the troop my son joined, there is a fair amount of cross-over from year to year, between committee and ASM positions. (It isn't excessive, but most of our ASMs have served on the committee in the past too) I think this is healthy because it also allows the ASMs to understand and appreciate what the committee does. And of course vice ve