Moving in to our first apartment?

My brother is turning 18 next year and I'm 16, we're going to rent an apartment together in Austin TX (when he's 18) and my parents will be right next door. I'm so stoked. My brother and I are close and we're mainly excited about decorating. We were thinking maybe like a vintage, old new york kind of design or maybe like, Ikea furniture, medium beige walls- more modern. I'm a Christmas person so I want something cozy and my brother says as long as it looks good, he's fine w/ it. What should we do?