Strategies To Lose Weight Fast

So i bought a few hanes plain white V-neck tshirts in MENS sizes, so it looks very boxy on my body. Is there any way I can cut//do anything to it to make it slimmer?

I’m 15 years old, my height is 5″3, and weigh 197 pounds. I’m trying to lose about 60 pounds so I can get to my actual weight to be, but I’m going to make it easy by losing about 10 pounds every 2 weeks or short in this month. Any advice I could know like how many jumping jacks, push ups, sit ups, jump roping, etc. that I should do to lose this weight.