My daughter is 17 and is 5'11 and she wears heels. She says she is taller then most of her friends so whats a few more inches? She wears an 11 shoe which is finally becoming much easier to find. Zappos.com carries a lot of cute shoes in larger sizes.
We buy most of her jeans at Buckle, she wears XXL'S. Joe jeans also run long.
My son is 6'5'.
I am the shortest one in my family now at 5'8"
I say wear what your comfortable in, if your not comfortable you'll be slouching all day/night.