WhAt CaN I WeAr?????????????

I have a birthday party to go to where I'm going to see all of my family. I recently lost some weight and I want to show it off but the best way to do that is by not wearing jeans. So tell me what should I wear? The party is for a 1 year old and it is going to be in a park. I don't want to wear sweatpants. I just don't know what to do!! So please send me links or just your opinion. Any help is greatly appriciated. Thank you so much in advance. <3