My 2 cents is that you need to keep your heart rate up. There is also some Tabata timer out there. I normally jump rope to the tabata app. I could do 1000 within 8 minutes, including tabata resting time.

BTW: I am 60KG at 162 cm. But folks commented me looking like someone around 50KG (consistent feedbacks from different people. So this is likely true). I do have a lot of muscles and I do echo the need for you to start strength training.