I'm 24 years old, have never raced anything over 8k. I stopped running for about a year after college, then started up again and ran a 17:15 5k about a year ago off of ~45 mpw. Have not done any races since then but have kept up easy running (7:00-7:30 pace), building to about 70 mpw. Recently joined a running club and am getting semi-motivated again. There's a half marathon two weeks from now, and one of the guys in the club is shooting for 1:19-1:20. I'm wondering if I can stick with him. Today we did about 30 minutes of ~6:00 pace at the end of a 17 miler and it was somewhat challenging, but still fairly comfortable. Other than that I haven't really done any workouts, with the exception of a fartlek-type thing last week, and occasional strides and hill sprints (1-2x per week).
Based on this admittedly vague information, what kind of shape do you think I'm in, and what would be some workouts that might indicate sub-1:20 shape? Thanks in advance.