It depends on two things basically:
1) The type of person you are. If you're quite open-minded, out-going, sociable, then you should have a great time, but this does also depends on the 2nd point below.
2) Who you live with. Lets skip the bull****, people who tell you not living in halls doesn't really impact on your social-life/freshers week, are chatting *******s. Generally, if you're not living in halls, then you have to either make a lot more effort to find people to go out with on freshers week (and weeks after), or you have to get lucky that on the 1-2 hour induction/registration you go to in the beginning of freshers week, you somehow manage to find someone(s) to hang with on nights out.