Those clothes look fine to me. I know I'm an old fogey, but jeans and a really nice quality mans proper white shirt in the very best egyptian cotton always look completely fantastic. If you are young and gorgeous, then so much the better. You can get away with anything. Just wear what you feel happiest in, never mind what anyone thinks of you. Be the shepherd and not the sheep.
I'm not very pro all this scruffy malarky and especially the trousers falling down thing. Oldies like me just don't get that one. We call them panty boys. When young men walk down the street holding their trousers up with one hand, they may think everyone is looking at them... and they are actually quite right..... but we are all chortling with mirth.
I'm sure there must be a good reason and we are just old bagginses ..... You don't have to listen to the likes of me..... I'll just go and find my teeth.....