Baby bumps

Something I'd like to know is how is it that at just 14 weeks, there's women that have massive baby bumps. I'm talking about the ones having just one. If the baby is about the size of large lemon, a beet, how is it that women look like they're about to give birth and it's their first child? I'm looking at these baby bump pictures and I get sad because I'm so small and I barely have a bump, when I do, it's bloat. It gets thoughts in my head that my baby isn't healthy and I won't know because insurance isn't kicking in and I'm far behind. So can someone please explain this?