BB I haven't done this race before, but it will be a good one for you if you are new to running and worried about your time.
There will be a lot of people doing run-walk rather than running all the way. I will be run-walking with my wife and two young children. We hope to finish in under 30 minutes, but if we don't, then we probably won't be last! (I was last once in a race, but it was a pb for me, so I was over the moon.)
Good luck!