I'm not entirely sure how long my ball pythons are, but I have 4 girls all born last November who are all different sizes ranging from 200-550 grams. There is no growth to age ratio. They all grow at their own paces. And Balls never really stop growing, it just dramatically slows down when they're older. And length isn't an accurate way to measure a snake alone. It should be compared to it's weight too. Just like a human's BMI as we all grow at different rates and stop growing at different heights.

Is your snake in shed? Sometimes stuck shed could be the reason for a wheeze.
I would bump up your temperatures to 95 just in case it is RI though. Just keep a close eye on him.