When will the belly fat go?

The belly is the last to go for most people. More intense exercise will definitely help, but ultimately it is just patience and losing that last bit of weight. Without a lot of exercise and/or surgery you might never fully lose it, especially at your age, unfortunately. There might be excess skin there. My belly area/muffin top was the very last to go when I did body recomposition, and I am working out hard 7 days a week. I've been at it for almost 4 months with only 11lbs to lose, and my lower belly area was the last to go. I'm still not where I want to be, but it's close. The lower belly is SOOO stubborn.

Belly flab is almost impossible to get rid of, especially if you have given birth before and it is worse if you had one or more C-sections. There is a tendency for the stomach to hang, and for the muscles never to go back to original. Some people are still able to minimise it by cutting off all carbs (I love my carbs, I could never give them up). I know people with washboard abs who have sworn never to go near sugar or carbs. Good luck!

Heavy weight lifting has been found to have a greater impact on waist circumference than other types of exercise, partly because it increases muscle mass overall, which then means you have a lower fat ratio at the same weight. But there is also a recent study which looks at signals sent by the muscles to fat cells, which seems to indicate there may be more to it even than that. In any case it’s never too soon to start lifting while eating at a deficit since it helps to preserve muscle mass as you lose.

Even so, for many people the belly is the last to go.

I'm 5'5", female, 123.8 this morning (toward lower end of my 125 +/- maintenance range), and not devoid of muscle, though not anywhere near a bodybuilder. I still have some obvious residual fat in belly, butt, thighs, though this is a healthy weight for me. While losing, these areas were also the last to deplete, and the belly area specifically I had to be probably sub-130 for the fat there to be less inclined to conspire with gravity to keep the skin stretched out.

Now, different women have different builds. I have narrow pelvic width, and zero breasts (post mastectomies, no reconstruction), so other women with similar genetics but wider pelvic spacing and/or bigger breasts might see more depletion of the mid-body areas at a higher body weight. Ditto for women with more muscle mass.

That, on top of the idea that different people lose fat from different areas in varied order, potentially . . . though abdominal fat tends to be a later one, for most.

I won't speak for you, OP, but at the top boundary of the normal BMI range (about 150), I was realistically still carrying quite a bit of excess weight (as in some folds/rolls in the abdominal area). My SW was 183.

I've read the studies saying that strength training *may* help mobilize abdominal fat in women (or others, but most of the studies I've seen have been of women - biased by my interests, I'm sure). I'm inconsistent about strength training, so haven't seen the effect personally, but that doesn't mean it's not true.

I agree that posture can make a big visual difference. Two postural issues that are common are anterior pelvic tilt, which pushes the belly area forward and maybe encourages any soft bits to drop downward; and kyphotic posture (not kyphosis, which is structural) a.k.a. "nerd neck" unflatteringly, that chin-forward, shoulders-rounded thing that so many of us have these days from computer/phone use and other slumping behaviors. If you look at some illustrations of those online (easy to find), you can look at yourself in a mirror and see whether they might be an appearance factor for you. If so, there are good YouTubes from physical therapists with exercises to improve either/both.

I see some people here reporting appearance help from "stomach vacuum" exercises, too, to work on transversus abdominus, though I haven't cared enough to do those consistently myself.