Dinghies are a good first project if you have never built a boat before.
The smaller plywood ones can go together in a matter of a few weekends, but in that short period you cover a lot of the skills needed to build something larger.
The strip plank dinghies will take a little longer, but again much useful experience is learnt which will help when you move onto a more complex project.
As a project for the kids to join in, dinghies are ideal. The boat comes together quickly which suits their eagerness to get on with the job.