I'm running at 8km/h. 2 miles takes me 25 minutes. To do 5k in 30 mins I would need to run at 10km/h (obviously). This seems impossibly fast to me, I ran at 9km/h for 4 minutes and my lungs almost exploded.
My hat is off to Roger Bannister, who ran 4 minutes at 24km/h back in the 1950s, and all real athletes!
It gets better, it really does. It doesn't always feel like it, but it does. Speed will come, keep upping the distance, keep trying to push how far you can run and the shorter runs will get quicker. Intervals can help too. I was a good few weeks past finishing C25K before I was running 5k in half an hour.
yeah what Andy said!
dont worry about it, speed will come later if you want it to.
Though once you start running a bit it does give you a great perspective on the pro-athletes times doesn't it! Mo Farrah runs 10K in the time it takes me to run 5 - its has to be inhuman 
Before I ran I never used to take much notice of the times that running athletes would do, then when I started running, I had a whole different outlook towards them...I see the times they're doing, the speed they're doing and I just wonder how they can do that! I have been running 6 months and I would like to get faster, I already do intervals on one run and speed/hill work on another, plus a long run and a recovery run every week. Yes my times are getting better but I don't kid myself I'm every going to be what I call "fast". I think I'm built more for endurance.
Endurance is good, don't knock it!!!! I'm built to just get it over with so I can have a cuppa
I was a bit disheartened when I reached week 9 and my final run of 30 mins but came back home, checked my mapping app and it was quite a way off 5k - I had to go out the next day and run for 37 mins to reach the 5k target! I am getting a little bit faster but am trying not to worry about the time too much - just trying to keep up the 30 mins of running each time is hard enough for my will power!
Help! I want to speed up
I need to feel motivated 
When do you start to increase speed?
