New to My fitness pal

Hello, My name is Holly I am 53 and 5ft 9in I weight 225 lbs. I started to gain weight 10 years ago I had always been very skinny growing up. When I got pregnant with my first child I weighted 97 lbs. By the time I gave birth to my son I weighted 207 lbs I was 22 years old at the time. I got back down to 117 lbs very quickly. My metabolism has really slowed down. My goal is to lose 70 lbs by next year. I want to do this right and do it clean.