You started 4 weeks ago and you are down 12 pounds. weeks are very short time frames to look at. Exercise is not required to lose weight. It can help increase calorie burn but if all you want to do is drop fat you can do that by just putting yourself in a consistent deficit. But that doesn’t happen in quick or linear ways. So many times you will see an initial change only to level off or hold at periods. This is normal as your water weight can fluctuate fairly substantially day to day or week to week but the fat comes off slow.
So the example would be if you are in a 500 calorie deficit a day which if done perfectly you will see 1 pound of fat a week lost. That can easily be masked by water weight and other changes. People need to be very careful to understand that the number on a scale just is a number and doesn’t show composition. SO if you weigh yourself weekly you could easily have lost 1 pound of fat but be up 3 pounds in water weight, so you looked like you gained. It is much better to think of your weight as a range that it can fluctuate in. For me that is 10 pounds. Staying away from a scale early on or at least not weighting all the time is a good idea too. The goal is to make changes you can sustain for the long term in a consistent way. And long term think months or years instead of weeks or days. The goal isn’t to lose weight. That can be forced if you want in various ways. Your goal is to find the balance so you can continue to do this long term. What most people do is go from one unsustainable way of eating (where they are gaining) to one where they lose but they never find that balance point. For me this is what IF allowed me to find. Now doing this will take time but if you do it correctly it can be life changing.