I think you could start them at their actual age. I stated Alexis in the 6 MO
water babies class and she was only 5 months so I don't think for that activity
in particular, 1-2 months makes much difference. Try it at least and see if
you and they are comfortable with everything that goes on. Make sure that you
have another adult helping you, possibly even a third. My husband and I both
got in the water with Alexis so that she could "swim" between us. From one
adult to the other. So it might help if you had three adults to the two
babies.

Good luck and have fun!

~Kimberly
Mommy to Alexis Iliana 07/17/99 and
Emma Elidia & Aislyn Gabriela 10/01/02
come see us...
http://www.babiesonline.com/babies/a/aislynemma/