So if I'm understanding your post correctly, you've been eating 1200-1400 kcal per day yet your weight has been stable at ~215 pounds. This either means:
Your total daily energy expenditure (TDEE) is also around 1200-1400 calories per day, OR
You're eating a lot more calories than you think.
Let's explore each of these in more detail.
Based on your height and weight, your TDEE should probably be 1800 to 2200 calories per day. Just your BMR or Basal Metabolic Rate (the number of calories your body burns per day just to keep you alive), should be ~1500-1800 calories per day. There are lots of reasons this could be lower, but for your TDEE to be 1300, you'd have to have a BMR in the neighborhood of ~900 calories per day or as much as HALF of what we'd expect. This would be exceptionally low considering your size. BMRs that low tend to only be seen in elderly frail women. To be clear, without having a metabolic test, we can't know for sure, but this does seem unlikely.
A more logical reason for this discrepancy is that you're actually eating a lot more than you think. Calorie overestimation is extremely common (unlike extremely low BMRs), thus I lean toward this as an explanation. I have seen some suggestions stating that the magnitude of this may be as high as 40-50% underestimated. In other words, someone could think they're eating 1500 calories, but they are actually eating 2200+. So where do people go wrong?
Misreading/misunderstanding nutrition labels. It's not uncommon for people to confuse a serving with a container of food. Sometimes, manufacturers will list a serving of something, but what you're actually eating may be 2 or more servings.
Accepting as fact the calorie counts on nutrition labels. In the US, calorie counts on nutrition labels can be off by as much as 10% before manufacturers would be expected to adjust the calorie count. Keep in mind, though that manufacturers are self policing here and really don't have a lot on incentive to make sure these are correct.
Many people simply guess at serving sizes, especially if it's a meal they made themselves. This can lead to wildly inaccurate calorie counts
Also very common when they are making meals themselves is to just look up a calorie count for a similar food, but this also can be really inaccurate.
Lots of people guess at amounts, thus you may think you're getting say 1 cup of a food, when it's actually 1.5 cups.
Speaking of measuring by cups, this also is wildly inaccurate. To properly measure calories, you really need to weigh EVERYTHING you eat IN GRAMS. Any other method just isn't very accurate.
I also wanted to touch briefly on your comment on exercise. While I think it's great that you're exercising, this really has nothing to do with weight loss. Lot;s of studies show that increasing energy expenditure through lower levels of exercise like you're getting typically leads to lowering your energy expenditure elsewhere throughout the day. This means you really have no increased calories burned and shouldn't think this means it's okay to eat more as a result.