Is 5'5 150 lbs fat for a girl?

If you mean fat as in overweight then probably yes. I'm 6'1 and 195 lbs, and my ideal weight is 175 lbs, so therefore im over by jsut 20 lbs, which isn't too bad for most people. Search for a BMI scale, input height and weight, and sometimes age, and check what your BMI is, or body mass index.