Need to lose 88 pounds

It depends on your stats, activity level outside of exercise, and how accurate you are in your logging. But you likely don't need to eat that little. I lost 60+ pounds never eating less than 1500.

I'd advise not to eat only 1200 calories a day. You might burn out and quit partway through because of the large deficit.

Instead, eat the calories MyFitnessPal recommends, including eating back part of the calories you earn for the walking. You'll be more likely to stick with it if you're well-fed.

I'm with daniip_la, going too low on calories can work against you and your goals. Also, racing toward a number can be counterproductive to making a long term change. Rather than race toward a goal, consider working at developing a way of living that you can be comfortable with for the rest of your life. Avoid short term sacrifices that will only provide short term rewards. If you focus on living in a healthy way, your appearance (and your body weight) will reflect the way you live.