Pushups advice

So tbh 15, 5'8 95kg yes I'm aware how high that number is but I dropped 3 kgs in 2 weeks after finding that out. I never really paid attention to my weight cuz I had better mobility then most kids of my age but I realized that and started running I'm nearing a 5k now but this is about pushups. Before this my baseline was 10 knee pushups but I found out that sports practical is soon so I started preparing. Yes I couldn't prepare in time but by the time it was practical I was able to do 2 full pushups like 5 days ago. Today's baseline was 4 pushups. However some really thin people say pushups are easy. But tbh I'm not sure about the science but since my upper body is heavier I'm probably pushing more than them and I'm fully aware about diet too. But the thing is i think my form is wrong although for me a full pushup is touching the tip of the nose to the ground while the body is flat I don't really think my body is flat while doing the pushup. If anyone has any advice I'd appreciate it just on form and what can I do to make everything overall better.