Stomach After Exercise is soft?

Well I've been working out almost everyday. My routine consists of an hour of aerobics, ten minutes of ab exercises, touching my toes ten times, 100 sit ups & 100 jumping jacks. I've been doing this for a few weeks & I've noticed a difference, My stomach is a lot more squishy than it used to be. I don't know what it means...shouldn't it be harder?