How many 1400 calorie ladies are out here

I try to stay around 1400, even though MFP put me at 1200. Haven't gotten off my butt and started exercising yet, but plan to eat at least some of those extra calories when I do! I have lost 5.6# since 1/1/13.
I'm 47 years old, between 5'5"/5'6", with about 30 more pounds to lose. Most days, staying around 1400 isn't a struggle for me, provided I eat enough filling foods with fiber and stay hydrated.

I'm 5.8" and on 1370 cals, which is possible a bit low based on my TDEE calcs, but it works for me. I eat back my exercise calories but not my hour a day of brisk dog walking. Some days I am hungry so I have a little more. This is a lifestyle change for me, so I want to listen to my body too. I've been loosing on average about a pound a week. As I cook for the family it's not always easy to log all my calories accurately, but I'm happy with the downwards shift.

I am currently set at 1200 (MFP set this for me) I am 5'4" currently 147 and shooting for 130. I am planning to start incorporating weights. Now mostly doing Zumba classes and treadmill. How do I know if 1200 (which I am frequently under) is doing me more harm than good. I am losing but don't want to damage my metabolism. Any suggestions are welcome.