Cute suit, great quality. My baby is 3 months, 13 pounds and the zipper is too substantial for his size. It zips up into his face and bothers him. We unzip it halfway and it seems to work, but also defeats the purpose of keeping the sun off his skin.
I imagine when he is a couple months older it will fit well, but it shouldn't be advertised as useful for 0-3 months. Would definitely encourage use for babies 5+months or older.