I know it can really be different from person to person. It depends on your prepregnancy weight, fitness, etc. I started showing right away but then just stopped growing thru my second trimester before I got HUGE in my third. My two friends are really tiny and they both look ready to pop even though they’re only about halfway there! My other friend who’s not so tiny barely even looked different the whole time. And yes, your age has its effects on a pregnancy. It’s been proven that younger mothers tend to have smaller and sometimes more premature babies. So take your prenatal vitamins, eat healthy, and excercise. It will do wonders. I was 20 when I had my daughter and she was 8 lbs. 10 oz. I swear that prenatal vitamins and lots of proteins (my big craving was salisbury steak) are responsible. Best of luck.
Love,
Sara