Wondering about their growth.

I have a 4 month old "normal" and im feeding her 1 pinkie every 5 days. I was just wondering, what will the snakes body length be at 4 months, 5 months, 6 months... and on and on. Can anybody give me a average growth chart for a cornsnakes life span?

There isn't a chart. There couldn't be a chart. Corn snakes grow at different rates due to genetics, differing feeding schedules, differing nutritional value of prey items, differing temperatures, etc..

Chances are, your snake could be eating larger prey items at 4 months of age. Dean didn't link to it, but there is a thread or two out there about the "Munson Plan" which is a good reference to see what size mice you should be feeding your snake, compared to your snake's weight.

Quick cut and paste:

-Single pinks (2-3g) every 4-5 days. (Snake = 4-15g)
-Double pinks (3g x 2) every 4-5 days. (Snake = 16-23g)
-Small fuzzies (5-7g) every 5-6 days. (Snake = 24-30g)
-Regular fuzzies (7-9g) every 5-6 days (Snake = 30-50g)
-Hoppers (9-12g) every 5-6 days (Snake = 51-90g)
-Weaned (14-20g) every 7 days (Snake = 91-170g)
-Adult (24-30g) every 7-x days (Snake = 170+)
-Jumbo Adults (40-50g) every 7-x days (Snake = 400g+)

My snakes that are about 4 months of age are eating double pinks every 4 days. The rest, that are slightly younger, are going to be moving from single to double pinks soon.