u/Far-Accident1228

I'm making a cropped top with 100% cotton yarn, but it seems a little stiff. I've searched for methods on Google and saw that I can wash it with conditioner, but I'm worried it will get too big and loose when I wear it. Can anyone tell me if the project will stretch a lot or if the difference wouldn't be very noticeable? Its my first time doing something so big and I do not want to mess it up.