My unsolicited 2 cents -- get small implants, and for goodness sake use silicone. Not only does silicone look better, they feel infinitely better from the point of view of the sex partner going to town on them. Yes, I understand the safety concerns, but if you want to be 100% safe, then don't have cosmetic surgery in the first place -- if you are going to have it, don't compromise on the result.

As to the implant size -- bigger ones only look good on tall, large framed/boned women (e.g. Brigitte Nielsen, 80's star Raven) or women with big floppy natural tits in need of firming up -- like Laura Lion (here is an "after" picture):

You fall into neither category. Get implants no bigger than say Beatrice Valle -- she is exactly your height and body type. Or look at Asa Akira if you need a more recent vintage example.