If you don’t run at all you should visit your doctor and make sure you are healthy enough to run. I was 24 when I decided to start running semi-seriously and I still went to my doctor and got the go ahead to start a training program. There comes a time when running is more about overcoming mental hurdles than physical ones. A quick visit will make you more confident in your body’s ability to handle a running regimen. Getting the OK from your doc will make future mental obstacles easier to overcome.
Start off slowly. If you haven’t been running it’s important to acclimate your joints because once we get rolling they are gonna take a pounding. Buy a pair of running shoes and go for long walks everyday. If you have a gym membership, hop on a stairmaster or treadmill and set it on a moderate incline and walk “up-hill” until you get tired. Build up slowly until you can jog a slow mile, then two slow miles, then three slow miles. Rushing into a training program increases your chance of injury. Take your time and start stockpiling airline/credit card miles while you work towards your running goals. The races will always be there and I’ll be waiting at the finish line!