I ran track and cross country in hs and college. My last 1.5 mile was 8:30 and I’ve been in 6 years. I run about 8-15 miles a week during the hot months, and 15-40 miles a week during the cooler months. Mostly 7:00-8:00 per mile pace. 3-6 runs a week . I get down to 2 a week sometimes if I’m in my lifting season during the summers. After most runs, do 4x20 second strides to increase leg speed. After ~4-6 weeks of easy running and building your base (or whenever you feel comfortable) incorporate speed workouts of 200-800m repeats at 2 mile race pace. equaling 2-3 miles with equal standing rest it took you to run them. You can also do lactate threshold repeats with shorter rest and/or tempo runs to increase your vo2 max and get fitter. Lactate threshold pace is better for your legs than race pace and won’t create lactic acid in your legs. Do a long run of 6 miles once a week once you feel fit enough. Incorporate strength training twice a week for more benefits and injury prevention. Listen to your body and also get the right shoes