First time? Pick one of three – Navy, Charcoal, or Gray. No light gray and no blue – those are too casual. And no black – that's for black tie which typically calls for a Tuxedo. Fear the Black Suit as it will be the last suit you wear.
A small pattern or dynamic texture that's not noticeable is perfectly fine, but avoid noticeable patterns until you're on your third, fourth, or fifth suit.