You specifically got told to dress nice... Is it a really nice old jumper?
When I hear 'nice' I don't wear clothes I describe as 'old' as old is reserved for things that look well worn. I have nice vintage stuff but I would describe them as 'old' so I'm wondering what you meant by old.
If told to dress nice I would never wear converse, on what planet is that nice? for casual I would wear pretty ballet flats or boots and for dress strappy heeled sandals or heeled shoes.
Black jeans are likely fine, black jeans photograph similar to black trousers unless they have ripped patterns or brand logos across the ass, etc...
Honestly, any time I'm told to dress nicely for a casual event I either grab a skater dress, tights, and shoes or dress jeans, dress top, blazer, and boots.
Trainers/flip flops/crocs/uggs, tight-fitting short dresses, shorts, tracksuits, leggings or anything described as 'old' really have no place being worn under the descriptor of 'nice' - unfortunately, you fell fowl of 2 of these, its a lesson learned through embarrassment but I bet you wont make this mistake again.