Congrats on your upcoming wedding! And it's always nice to see women discover lifting.
This isn't a simple question because it depends on what your goals are, and your current level of fitness. I apologize if I'm telling you stuff you already know.
To loose fat intelligently and in a sustainable way, you need to create a gradual calorie deficit.
To gain muscle, you generally need to eat enough protein to build AND create a calorie surplus. You might see your scale weight go up, but your body composition would improve. You may even loose inches. Unfortunately, you can't spot reduce your mid-section but it should improve under either plan, IMO.
Yes, 7 months is enough time to see some really nice changes to your physique. When you need to "start prepping" depends on your current level of fitness/ how much fat you want to loose, etc... If you plan on trying to loose a pound of BW per week, that would give you an idea of how soon you could reach your goal. Without seeing your physique, or knowing your current body comp, it's hard to say if that is a reasonable goal. Not everybody needs to loose scale weight.
It sounds like you're already doing it right, but you'd need to keep track of your food in a more precise way to see where you are at in terms of maintenance calories and macros for people to give more detailed advice.
You have 7 months, so I'd avoid drastic dieting down for your wedding because you'll almost certainly yo-yo right back up. Slow and steady and making changes you can maintain is the best plan, and the least likely to mess up your metabolic rate.
I hope this helps!