I said this to someone else earlier, but am going to repost here as well.
My first run (well, sort of jog) was today - and I lasted 10 mins. LOL!
Having read other people's experiences, I know that for some people it will very hard going at first & I realise I'm one of them. BUT - I've just done 10 minutes more than I would have done otherwise. So maybe it might take me 10/11 weeks to get to 5k, but honestly I'm too old & too grumpy to care. 10/11 weeks ago, I wouldn't have even considered this, it only occurred to me to start this 2 days ago. If I can get a bit healthier by this Spring, then I'm doing better than I was last Spring.
To everyone who's just started - don't beat yourself up, I know I'm not going to! Go at the pace you're comfortable with & what your body can handle. I'm pretty sure my trainer "Jo W" won't mind.
Take care & remember "Every Little Helps".