You can't tone skin or fat, you can only build muscle. Right now there is a lot of fat on your belly, and as that shrinks your skin will feel loose and mushy for a while - it takes longer to catch up. And there may be extra looseness from having kids, too. A lot of the skin elasticity is genetic. Do not be fooled into buying creams or lotions that promise to "tone" skin.
Concentrate on your weight loss, stay hydrated and eat enough fat and see what happens. Will you need or want a tummy tuck? No one can tell you that. If you read old posts, you'll see that it took some people's skin a year to "fit better" after weight loss.
Just relax and settle in to your weight loss.
It's about commitment, not motivation.