Shein

Im just now in my 30s getting into fashion and I’m experimenting with different styles to find my look. I want to order from SHEIN but I’m not sure what size to get. I’m a 4x typically in Walmart brand clothes but the models of SHEIN size 4x look smaller than me. I’m 5’4 350 if that helps. Any similar sized ladies order from them and if so what size