Anyone have kids when you were younger and want more later in life?

I'm 33, almost 34. I have 3 kids, ages 16, 13 and 11. I have always wanted more but hubby didn't so nothing was permanent. Now after all these years, hubby changed his mind and wants to try. I'm so torn. I wanted more while the kids were still young. Now the kids are older and we are so close to being just us. I don't know what I want but I'm afraid I will regret not having another. Anyone out there have kids when they were young, like teens and 20s and then had or wanted more while you were older?