I turned fifty last month. I’m still trying to get my head around the number. When I was a kid, thirty seemed ancient beyond conception. So that makes fifty nursing home material, right? What staggers me most is how I knew it was coming and I didn’t really think about it in advance. I’ve been avoiding sitting down to look at it closely, which is odd. I usually love to pick things apart.

A lifelong friend who is smarter than I am realized the distressing aspects of a fiftieth birthday and came up with a way to think differently about this milestone year. She defined a challenge for herself so she can grow older without regrets. Focusing on having new experiences and learning new things is a direct and effective way to challenge our assumptions about aging.

Despite her good example, my birthday came and went without me knowing how I feel about turning fifty and what I should do about it, if anything. I started looking around for answers, but most of what I’ve found has been more disturbing than reassuring.

I picked up a magazine called Fifty & Better at the doctor’s office and started to read an article about conscious aging. I still don’t know what conscious aging is about because the first paragraph had me hyperventilating. It said that when we reach fifty, it’s time to consider how we want to spend the last third of our lives.

Third? THIRD?!? That means it’s over at seventy-five, and I’m not sure I like that idea. Twenty-five years is a blink of the eye. I’ve been out of college for more than twenty-five years now, and it doesn’t seem all that long ago. I’ve got relatives in their eighties and I’d like to think I can make it there, too. My sexagenarian friends were generous and told me fifty is only halfway. Even my conservative friend put forty-five at halfway, meaning that at fifty, I have 45% of my life yet to live.

As I was trying to get that disturbing statistic out of my head, I came across more exciting news. Apparently, the unhappiest adult years are fifty-one to fifty-five, which puts the pit right in front of me. I’d like to think that my unhappiest years are already past. I went through an unhappy marriage and divorce. What could make the early fifties any worse? The only explanation I can come up with is that most people get their first colonoscopy at fifty and it takes a good five years to forget what it was like.

When I think about aging gracefully, I look to my in-laws, who are in their nineties and have been living independently until just recently. My father-in-law has taken some dramatic tumbles over the years, and while he’s had some horrific bruises, he’s never broken a bone. Part of the reason they have been so healthy for so long is all the effort they put in to staying active and eating a healthy diet throughout their retirement years.

As a result, I’ve made daily exercise a new priority. I am getting up early to get to the gym. I’m trying to figure out who to talk to about my mildly cranky knee, because I’d rather do PT now than surgery later. I’m following through on mammograms and physicals and blood tests and, yes, even colonoscopies. I’m trying to make informed decisions about my health. I want a long life if I can get it, but a healthy life would be even better.

Fifty isn’t the finish line, it’s the starting line. The choices I make on a daily basis will determine what shape I’m in when I finally reach the real finish line, whenever that day comes. For me, turning fifty is like living in Colorado: not once in my youth did I ever imagine myself in this place, and yet here I am. Colorado has turned out be fantastic, so I have high hopes for the years to come.