Hi.
I am only just into my 40s. I am 5 ft 11. And I just stopped smoking last July 3, 2016. Before that, I was a HEAVY smoker, for the last 25 years.
I was ok for about 1 month, maybe 6 weeks after I stopped smoking. Mostly because I was white knuckling, EVERYTHING. But soon after the first month or so after quitting, I literally piled the weight on like NOBODY'S business. I gained 100 lbs in 6 months, without even binging.
I am now 2.5 months back on the straight and narrow, of 20g carbs TOTAL per day. And in the first two months, at 20 years younger than you, no other health issues, and A LOT more overweight than you, I lost 7 lbs total. And THAT, was in the first 72 hours... and then I just fluctuated within 2 lbs of that, for the next TWO MONTHS.
I have JUST in the last week, started to lose a few pounds again. So while my post is kind of depressing (to me) to read, I am actually trying to encourage you. It DOES come off, but sometimes it is really slow. I mean, at my height, at my weight, and at my young age and with no thyroid issues, there is NO way ANYTHING should have been this slow. But it is, and there is nothing I can do about that. So I would encourage you that this way of eating is for health, and that results are sometimes slow to catch up, and slow to sometimes accurately reflect the correctness of what we eat on a day to day basis.
My advice would be to stick with it, but as you are a very petite person, also be mindful of calories, not just of carbs.
Lastly, I would also share that last summer when I was walking 3-5 miles, 5 days or so a week... I literally lost NOTHING. For many more weeks than 4.
Sometimes other people's experiences help encourage us that we are on the right path. It is frustrating when some people seem to drop 40 or 80 or 140 lbs or even more with little seeming effort - but the truth is, it's always a dedicated effort.
Good luck, because you can definitely do it!