I had a successful cake making business for a few years and had not one lesson in cake making/decorating. It all started after I copied a Santa in his sleigh cake for the school Xmas fayre. I don't know if you want to be proficient at novelty cakes, involving more sculpting and shaping than piping, or you want to do it all. I wasn't professional level at piping but after practising I was good enough.
Just go for it. A good market often has a stall of cake making equipment, including boards, icings and decorating bits and bobs. Or try online. To start I would just get basics, much of it from major supermarkets, either fondant icings and/or icing sugar and a good piping set and just set to. I started with a Mary Ford book, which I still have. Step by step pictures help you. It's not a starter book tho - even tho that's the one I used - lol! Have a look in the shops and buy the one which appeals to you. When you're ready to have a go on a cake upend a cake tin, cover thinly in fondant and away you go.
I only make for reles these days and I much prefer the decorating to the baking. They love the personalised touch and that you have made it special. It's very satisfying. Good luck.