Am I kidding myself??

I have coached a (male) work colleague from zero running to doing Cardiff Half in under 2 hours in 3 months.

If you're mechanically efficient and not injury prone with a normal level of fitness then 3 months is perfectly fine.

Google "Hal Higdon" and have a look at his beginner half mara training plans.

After having never run in my life I started a C25K program five weeks ago (4 weeks to go). There is a half marathon in my town on November 17. I'm managing the steps C25K program by pushing myself (I haven't been interested in being fit until a few months ago).

Is running a half marathon in 3 1/2 months from now an unrealistic goal?

Running a 5k or running a half are nothing alike, just because you can do one, does not mean you can do the other. I ran half’s several times a year, for years. But every time I entered a short race I brewed up, and ending up walking.
But for your question, it depends on how much free time you have, can you spare the time to run 5 days a week one being on a weekend. If so then yes you have plenty of time to train.
Start slow, and pick three days to train, you need to do at least a short run of say 5k, a training day where you do hills and fartlec, and a longer slower run on the weekend.
In 4 weeks time you should start to increase you shorter run until you can run 6 miles, and you longer run you should aim to be running between 10 and 11 miles three weeks before the race. (if you can do 10 miles you can do 13 miles) by week 7 you should increase the days you are running. Running is mostly mental, once you can run 5 miles; you can run 7 miles or 10 miles. Only your mind can stop you.
Your weekly Mileage depends on what you want from the race.
If you just want to Run it and finish, 1 ½ times the distance (1 ½ x 13.1 =19.6 miles a week in the last month of training)
If you want to run it and feel good when you finish 2 times the distance (26.2 miles a week in the last month of training)
If you want to race 3 times the distance. (39 miles a week …

totally doable. you need about 10 weeks to train, assuming you can run 3 miles to start with. Sign yourself up - that's excellent motivation.

I say no! Go for it. Train and eat better, sounds like you made youself a goal. now go get it. I think its fantastic. You gotta try it, that way you can say you did it! You might find that it opens a whole new healthy life style you didnt even know you were capable of achevieng. God Speed!!:bigsmile:

I ran my first half marathon this February only 2 and a bit months after having a baby. I did not run at all throughout my pregnancy and had only been running for a short time before that. It is possible if you have the time to do the training, don't do too much too soon. Find a pro if you can that can set you a plan that you can stick to. Good Luck! Let us know how you do.

I don't typically accept the term "unrealistic goal", I've seen way too many people conquer harder obstacles to say anything is unrealistic. Just get after it and do your best. If you don't get it the first time use that as motivation for the next one.