I guess I'll take the volcel word back.
Your plan is solid. Although, it's a bit strict ngl. Make sure you're not loosing more than 1% bodyweight/week or else you'll loose muscles. And 1g per pound of lean body mass is ideal protein requirement. For you it should be atleast 150 grams.
One small tip I'd give would be to weigh yourself every morning after waking up and pissing. And record that weight on a weight tracking app. This will help.
Since you're eating 1200-1500 cals you'll feel really hungry throughout the day. Make sure you're eating lots of protein and fibres( under Calorie limit ofcourse) and drink atleast 10 glasses of water.
Set a weekly goal. If you weight 85kgs then ideally you should be loosing 850 grams per week. Make sure you're like 84- 84.2 kgs next week. If you're loosing to much too quickly then crank up the calories a lil bit.
Also, keep in mind you'll loose water weight first you it might look like you've lost a few kgs after dieting for a few days but don't worry it's mostly water. And also, don't worry about daily weight fluctuations.
If you follow this routine then you'll be 10-12% before 2021.