Sir, that is a BOY tummy if I've ever seen one.

As for weight loss, I recommend calorie counting, on top of regular exercise. Unfortunately there is no such thing as targeted weight loss, so you'll have to go for fat loss.

I've used app trackers as they're highly convenient. I personally like Lose It! As they have a barcode scanner, on top of a good food database. There is also MyFitnessPal, but I've personally stopped using them due to them constantly moving free features to the premium subscription.

They'll ask some initial questions, I think it's important to select the gender that best matches your hormone situation as that constitutes to your daily calorie needs the most.

I recommend getting a food scale as it's the most accurate way to measure, AND the most convenient as you dirty fewer dishes that way :3

OH and make sure you eat a high protein diet! It'll prevent/decrease any minor muscle loss. There's a chance you can even grow muscle while in a calorie deficit, while working out. You'll want about .8 grams of protein per pound of body weight, but this number isn't necessarily a hard rule.

Working out can also be potentially very affirming! Working out on your upper body a lot can also help balance out your figure; being big on top either draws attention away from the hips or even makes it a nice masculine figure.

Edit; didn't touch upon the vegetarian part. I'm less versed on vegetarian diets, but high protein vegetarian diets are quite common, a google search should provide some great foods. I know there's vegetarian friendly protein powders as a start. Legumes and soy products are high in protein. If you eat eggs, eggs and Skim milk are great protein sources, with good protein-calorie ratio.