My sister and I are due 2 days apart with our first. Our bumps are such different shapes, and are carried so differently... People tell her she looks bigger but when we measure my bump is a bit bigger, I'm just very tall so makes everything look more proportioned...
Get used to the opinions on your bumps, all day at work I hear from patients that I'm either huge for 34 weeks or super small for 34 weeks (obviously depends on their experiences- because everyone is so different!)
Everybody is different. Being that it's her second pregnancy is probably why she looks huge. They say you should gain 25-35 pounds during your pregnancy. I'm sure your baby will be fine.
Yes your baby is growing. Don't compare your size with the next. Everyone is different. My SIL was huge. Gained nearly 100 lbs. Went over her due date and her son was barely 6lbs. I gained only around 30 lbs or so and had my son early and he was knocking at 7. Size doesn't mean anything. Sometimes some mothers retain more fluids than others making them bigger than the next