I am 16 years old female. I'm 155 cm and about 68 kg.

We're still in quarantine in Mexico and there's no so many dietitians available, and the risk is high. So I just started my weight lose journey by my own, but honestly I have no idea what should I eat and how many calories. I eat over 1000 calories per day but no more than 1200. I also do 15 to 20 minutes of cardio or 500 jump ropes a day. When I was 13 I did a very restrictive diet and I lost around 5 kg in 1.5 months, but after returning to my old habits I gained even more weight and stretch marks. So I want to lose weight as fast as possible (in a healthy range), I just don't want more stretch marks or flaccid skin :( Even if I am young, I'm covered by stretch marks.