Give yourself plenty of time to gradually build endurance while keeping your risk of injury low by choosing a race at least 3-4 months down the road (like the one you are doing in May).
A modest amount of mileage will get you across the finish line feeling strong and well-prepared. There are all kinds of training methods, but keep it simple for your first half-marathon. Depending on your current fitness level, your weekly training schedule could start like this: 2-3 short runs, 1 medium-length run, and 1 longer run that gradually gets longer each week. Every 4 weeks or so, reduce your long run by several miles to give your body a break, and get back on schedule the following week. Increase your total weekly mileage by no more than 10% per week to avoid getting hurt; if you’re doing 20 miles this week, don’t do more than 22 next week. Strength training twice a week will round out your training plan.
At least once a week, take a day off for rest and recovery. And, while running should be the foundation of your training program, consider cross-training with activities like swimming, bicycling, or group fitness classes periodically for a mental and physical break from pounding the pavement.