Body Fat Measurement

I joined a new gym 3 weeks ago and finally started lifting. This was after 3.5 months of diet, exercise and strenght training. My trainer decided to measure my body fat. He used a hand held devise. I am 5'2" tall, 118 pounds and 56 years old. After plugging the necessary information in it came up with 30% body fat. Now I can not accept that after losing 20 pounds I'm still at 30%. That's nearly overweight! Is it possible that there was something wrong with his device? Also there was another trainer that said if I wanted that to change I needed to change my diet. My diary is open, help yourself and look at my foods. I think I eat healthy and I workout 1 -3 hours a day. Why on earth would my body fat be so high?