How do I find out if my charachter is force sensitive?

You have to find a Jedi with the Force Test skill/ability and convince them to test you.

Check this out for more information:
http://rules.swcombine.com/character/force/

(I tried to make it a link but for some reason it wouldn't work :/)

thanks do you know where I could find one of these jedi that will test me?

You'll have to make friends with one of them and ask.

Most of them are on the IRC client

Bugging them to test you is usually a good way not to get tested, you're probably not force sensitive so just wait till the opportunity to get tested slaps you in the face. I'm sure most factions are capable of organising a force test occassionally.