Pacing a 5k race

I’m a few months into running, have completed the c25K program, and have focused on general 5K training for a couple of weeks. My first 5K race is today and I’m worried I won’t know how to pace myself correctly. I do not own a watch, do people use their phones for pacing themselves, or do I try my best to go off body feel? I’m still learning how each pace feels and am worried about jumping the gun and burning out, or underestimating my pace. Any tips are helpful, thank you!