What's the age gap between ur kids n the baby in ur belly

Barb
This is my 3rd child 
My 1st born is going to be 12 soon 
My 2nd born is going to be 10 soon
And this baby is due in February so that's a huge age gap so since there's been so many years since I was last pregnant this pregnancy feels like if I'm experiencing it all for the first time especially since all of the symptoms I have during this pregnancy I didn't have with my other two in the past from what I remember anyway lol