Check out your local YMCA. They offer plenty of options!
I'm an old-timer swim instructor myself... you will have a blast!
YMCA. My children both take lessons there. You can start at 6 months. My 8 month old will be starting this summer and my 2 1/2 year old started at 6 months and he begins one on one lessons with the instruction this summer. They do a great job and make it fun. Waterbabies and Watertots is the first until they are 2 yrs. or ready for 1 on 1 lessons and you go in with them and sing songs and teach them basic moves like kicking, blowing bubbles, etc.