We do it all the time. Of course we do. We travel in time. If we use past and future tense, if we say "I had a pony," or "one day we will get a pony," we are travelling back and forward in time. In our minds. It's useful to have this capability, especially if you can tap into some positive feelings while you are on that journey.
For me, that's a kind of meditation. When I am feeling stressed or upset, I put myself in a place in my past where I felt safe, where I felt loved, where I felt secure. That tiny little 'ping' of recognition of a feeling generates a dose of positivity that can go a long way toward soothing the present and smoothing the way to the future.
It's so tempting these days to stay focussed on the present dramas. The kind that set your teeth on edge and make you clench your jaw, clench your fists. Sometimes I find myself curled tightly into a fetal postion when I am in bed, and I recognize that is because I have allowed myself to be made small, to be pressed down, to feel powerless in the face of the present.
I know it is a good thing to stay in the moment, to live each moment. But I'm also aware that a bit of reminiscing or dreaming can be a powerful tool to make that possible in a healthier way. Exercising our ability to do that kind of time travel, whether we are remembering all the details exactly as they happened or not, is a way to generating some epiphanies about who we were, who we are, and who we may be.
So climb into that time machine whenever you like. And let yourself feel how it was to be a kid with a pony, or how it might feel to get one soon! You might be surprised at how much good it can do in your world.