I have now been running for around 9 months since starting C25K - but I did something else for around 10 weeks before starting.
I am 67 years old, and had not done any cardio exercise for many many years. I did do a bit of walking a long time ago - but that was indeed a LONG time ago. So when I got the thought that I wanted to do something, I was absolutely honest with myself and appraised myself closely. I didn't like what I saw.
So - I started out on my journey by walking a few times per week for about a month-- up to a distance of 5K . I got to the point where I could walk 5K in about 50 minutes - and I started to think that perhaps I could even run a little. I found the C25K programme but frankly decided ( in line with my self appraisal) that it was too much for me. So I completed this programme first 5K run: 7-week training schedule for beginners mayoclinic.org/healthy-livi... It is similar to C25k, except that it is completely run/walk and is much "easier" than C25K . For the very first run , you only run for 15 seconds at a time - with the remaining 45 seconds of the minute walking. It does actually get you out eventually to run/walking 4 miles (6.4 klms)
Many here successfully, start out and complete C25K -- but others struggle, even if that struggle is only psychological (which probably mine was) . So the above programme, when used as a "warm up" for the real deal (C25K) is highly recommended by me for those who find that C25K is too much at first.