In reply to Ander:
Can we keep the regurgitating of Lydiard as gospel to a minimum please, it isn’t and talk of periodisation is of no help to a relative beginner.
In my experience most people new to running, especially when they are in there mid thirties like the OP and myself when I started a few years ago is that they are a few pounds heavier than their ideal running weight. Regular running will help shift that weight. Their body might need reminding that it can run for 60 or 90 minutes or longer without needing to stop, regular running will help with this. Regular running will make you a lot fitter.
These will probably the biggest performance gains you have in your running career. I took 11 minutes off my 10k in seven months (50 – 39), since then I have only been able to chip away at that time.
I think training with a group really helps, as a beginner, I spent club nights working really hard to keep up with the group, I got much faster very quickly.
Speed work is great and I love it, but then I am told I do far too many fast miles. Mainly I just enjoy running and running fast is more fun than running slow.