"Ma'am, can I help you with that?" I nod and unkink my back while the boy collecting carts in the parking lot at the grocery store bends down and scoops up my fallen sunglasses. He does it in one fluid motion that reminds me of a surfer riding out a wave. No biggie, man. It is a biggie to me as I try to stand with the dignity of a young-ish woman. I give up and, to relieve the pressure, lean against the automatic door, keeping it from closing and "letting out all the bought air," as my grandfather would say. The boy hands me my glasses, and I place them casually in my hair like I'm not really "ma'am" material. Then I shuffle into the store like an octogenarian and do my shopping, ever so subtly leaning on the cart for support. I injured myself doing young things. I can be proud of that at least. Biking in Tahoe with your husband should count as a win. Of course, if you've got a bad back to begin with and your bike has no shocks to speak of, you should probably use the adult side of your brain and correct course. But it was the first time I had been kid-free in three years – the first time I'd ever left my youngest overnight. Two whole nights without a clock. I was drunk with freedom. The ride itself was beautiful, following a river that hugged the edge of mountains dipped in snow. It was the kind of place you expect to spot Robert Redford around every turn. It was good to be young and move my body again, to breathe in the pine scent that grew stronger as the morning warmed into afternoon. Except, as the grocery kid reminded me, I am not, in fact, young. After a day on a plane, my back seized up so completely that I found myself thinking things I'd never thought before. Things like: "Wow, that's a long way down to the toilet," and "If I pick up this dishtowel from the floor with my toe, does that mean I can't use it?" I had to walk with my hand pressed to my lower back to relieve the pressure. If I had a cane, I would have used it. I'd tie a ribbon on it like women do their purses…chic it up. My back is still so bad a week after we return that I have to ask the nurse to lift my son out of his wheelchair to weigh him. He's five years old and 40 pounds and picking him up on a good day is like lifting a gangly calf. We are at the developmental clinic for an assessment so we can start Botox to help relieve some of the tension in his arms and legs. I am optimistic. This will be a new step forward, literally. But something about the appointment beats down a place in my heart that I thought had been effectively desensitized. Maybe it is rehashing all his medical history. Maybe it is the way the doctor reports her findings to the resident-in-training, sharply clinical without the layman's words to soften it. Probably it is when they try to get my son to walk without his braces on his legs, barefoot down the hall. The tiles are cold and people are milling about at the nurse's station. He has an audience. I move down the corridor to give him an incentive – someone at the end of the rainbow. As he is about to try his first step, a man, somebody's dad, comes out of the bathroom and passes between us. It is just a second, just a moment when he cannot see me nor I him, but it is enough. He begins to cry. His feet shake and are already alternating from red to white in turn with the pressure on the floor. He will not and cannot take a step. I limp to him when it’s clear he cannot get to me and take him from the doctor, lifting him and cradling him in my arms like a baby. We fall into a plastic chair before my back gives out. I blink back tears, my face hidden in the crook of his neck so the doctor will not have to deal with a distraught mother, and we can move on with our appointment. Clearly, Botox would be in our best interest. I will go biking again, if only to search for Robert Redford. And my son will try to walk again. Some days will be better than others. We will hobble through it together. We may be slow, but we will not stop. What makes us young is not our body's ability to do what we ask of it. What makes us young is that we continue to try.