If it's very cold outside, you tell yourself 'if it's too cold after 10 minutes I'll come back in'. But you never come back in. It's a matter of getting started, nothing else.
We are funny creatures.
I used to always want to quit running ASAP, and the feeling just didn't go away whether I ran for five minutes or an hour. Fast forward some years, I'd gotten into cycling, enjoyed my rides and was in a much better physical condition. I also had a heart rate tracker and was used to training with heart rate zones. So one time I went for a run, first time in years, and tried to stay in the <60% HR zone. I started at my normal speed, realized my heart is racing, slowed down and eventually realized that even at my slowest possible running speed I'm going over my heart rate target. I had to settle for alternating between very slow running and walking to keep the exercise level light. Of course, after a couple of "runs" i could keep up better, but still running at any kind of speed is hard exercise for me.
I gather this is a common phenomenon, and most beginners run way too fast.