If you are interested in RC sailing then our advice is the following:

Establish which is your local club and ask which class(es) they race. Buy a second-hand boat (almost any one will do providing it sails). Get sailing as soon as you can. Plan to spend the first year learning about (a) the sport at all levels and (b) the boats used in competition. Plan to up-grade your boat after the first season to one that you have chosen carefully, based on what you have learnt.

We would not recommend buying a kit or building from a plan to any newcomer to the sport. We would not suggest buying a brand new boat either.