Some excellent advice here... Only thing I can add is..
Be careful when buying sets. In other words.. don't make your final decision on if you like a medium or not with what you bought. The reason I say this is (and I am mainly speaking for watercolor now since that is the medium I use.. but it is equally valid for the other mediums as well) is that the quality of the paints greatly varies. You can buy watercolor paints for $1.00 at the local Dollar Store.. or you can spend $8-10 / tube (or more) at a specialty store. The color, application, longevity, texture, etc will not be the same.
So use what you have to find what is comfortable to you and suits your taste.. But don't necessarily look at the quality of the finished works and say "This medium will never do for me"
Just My Opinion