Yes it's very good. Depending on lots of factors, 10 mins / mile is the general average starting point.
Just go out further and longer. You may need to slow down a bit but you're starting from a very good base. How many days a week should I be running? What kind of distance should I be increasing per week? Is eating gonna be a major factor? Sorry about all the questions just curious.
I'm happy to be in a position to answer!
All depends on what you want. It's as simple as the more you run, the faster and further you go, and if you weigh less you go faster.
Extra weight is your enemy so get as light as you can, but leg and core muscle is worth the weight up to a certain point.
Eating, just stop eating cakes, sweets and rubbish. A balanced diet outside of those will give you everything you need. Try to eat more protein normally and more carbs the day or 2 before a race / long run.
Everyone has an opinion on how much to increase per week, how much you should be doing etc. I just think you run as much as you can whenever you can because life dictates you'll have to have days off now and again. If I could I would run every day (and sometimes do). If you're already at 8 minute miles, you already have a decent fitness base so you'll breeze up to 4, then 6, then 8, then 10. Generally for your first HM you don't need to train above 10 miles. My only advice is to start each run slow. It's tempting to go out fast but you absolutely have to wait 5-10 mins before pushing on. The time you'll make up on the rest of the run will more than compensate for the slow first mile.
Something like this would be the standard running schedule until you find something that suits better:
Monday: easy run, distance depending on how you feel.
Tuesday: rest
Wednesday: 4 miles fartlek (pick a random point and sprint to it as fast as you can, jog slowly while recovering, then repeat)
Thursday: rest
Friday: 4 miles medium effort
Saturday: rest
Sunday: long run, step up 2 miles every week to 10 miles, then reset it.
On your rest days you could do core work, like planks, pull ups, push ups, kettle bells, free weights etc if you see fit. I did 7 miles today in a hour . I felt like I had possibly 9 if not 10 miles in me but started to get a slight pain in my knee so decided to stop. I decided to slow it down as I wasn't progressing as much as I would have liked. Also i haven't trained as much as I would have liked and I'm spending more time building my core strength as I felt this would be very important due to my aches and general tightness the next day.