Well, im no pro, I havent yet got to play in an actual competitive tournament. But I will say that you dont need EVERY club in your bag, but you need more than an iron, a wood, and a putter.
You could skip a few irons. And i'd get a 3&4 hybrid, and a 7&9 iron, with a pitching wedge, sand wedge, putter, and driver.
None of it has to be expensive, and there is great deals out there. Callaway Big Bertha irons are cheap everywhere right now. Especially online. Goftown, golf smith. My dad got a full set of Taylor Made burner irons (4-pw), 3&4 Hybrids, a 12 degree burner driver, and a beautiful Taylor Made bag for under 600$. Used, but still like new.