Most skills won't go up to ten. 1 just means you've learnt the basics and can use it. Every step up is a full level of training.
It also depends on the individual character's Stats. Someone with 5 Force sensative will be better with level 1 Force Power than someone with 3 Force sensative and 3 Force Power. It really depends and it's hard to be technical.
As for the plot, you're not suposed to be writing a history on your character. Write about the future, what you want to do. Your history can come out in the story through conversation with other players or something.
A master that takes you on for trying to steal his lightsaber will have to be merciful and kind. You're master will also be wise and fair teaching you well. If you still fall to the Dark side with Derrik, I'll be surprised. But you'll get plenty of involvement in the main plot and anything can happen.
I would add to your character flaws, emotional problems. The Death of your parents driving such a smart wise kid to life on the streets with poverty and theft...definetly emotional problems. It's going to take a very compasionate master to help such a troubled youth.