Basically, a pastry chef cooks pastries. I don't want to be so blunt here. Pastries are food items that are prepared through baking. Cakes, pies and similar dishes would be examples.
In order to be a cook, you have to love food. You have to be open to taste all things...even an octopus with peanut butter on it. Or a pickle with peanuts. You have to have a stable stomach like me....
Chocolate chip cookies.... little easy desserts...veggies....potatoes. You could also have a go at a traditional dish like shepher'd pie or spag bol if you have a good recipe.