Mini Success; It has been only 4 days and lost a little bit of weight

So I have started eating under/above 1500 calories, (1520 being my TDEE) for the last four days and have lost about two pounds. It is probably water weight and I should not be really excited, but I am still very excited since I am doing IF with a little bit of skimmed milk in my coffee in the breakfast and pretty good lunch and a very hefty dinner. Heck, I had about two bowls of Chinese dumplings yesterday (24 dumplings) and half a brownie, and also a little bit of rice for dinner. Never felt this good since ate whatever I wanted for dinner and still am losing weight.

Background information about me, I was 110-114 pound for most of my life, then binged on anything and everything for a whole 10 months and gained about 22 pounds and then for the next 3/4 months, have not binged but did not eat healthily either, gained another 6/6 pounds putting me in a position where I weighed 140 pounds this 23rd February and now for the last four days, eating under/slightly above 1500 calories and losing weight. Also I am 29, F, only 150cm. TDEE is about 1520 calories, so in order to lose weight I am supposed to eat about 1200 calories, which seems very impossible to me given my record of binges and eating whatever I wanted my entire life.