Yup, I had 2 12 month olds start at the same time just this past fall. It's busy but very doable. Your days go by fast. Right now I have enrolled in my daycare..

1-12 month old
2- 16month olds
1-2 year old
1-2.5 year old (starting Feb. 1)
1- 4 year old.

When the 2-12 month olds started I had 4 kids here under 2...it was fine but you have know you can handle it. I was very very busy and nap time was a saving grace but I knew I could handle it. Now everyone is walking except the 12 month old and he is fairly close.