I am very slim, 177cm/56 kg. my chest is flat, I sometimes have a tiny bit of a belly.

I want to start going to the gym- to get a better shape, athletic and broad.

do you think I will have to change my wardrobe after that? just curious.
some items fit me not so well because of my slim body shape; however I did tailor some of them, or bought an XS size.

Two of my trousers are a bit two tight at the moment (after tailoring), I hope the gym will help it because I know some guys with a 6-pack which is still prominent.