Most of my hatchlings are between 12 and 16", and quickly get up to 20" or more in the first couple months.

Try not handling her as much, and get her nice and chunky and well fed. A striking ball python usually sounds to me like an insecure ball python. Make sure she's settled in and feeding well, and try just leaving her along for a couple weeks to relax and chill out a bit. Start small with 5 min or so of handling, and work your way up.

Some snakes never really like or tolerate handling well. She may be one such snake.

-Jen