Mindfulness has received a lot of attention in the last few years and for good reason. However, while there are some great advocates out there, I still think general understanding of its benefits are limited. I see mindfulness as another method in our toolkit for preventing the mind from causing itself turmoil! It can take a while to master and have impact but it pays off if you stick at it.
Research has shown that minds that are more easily distracted are more prone to rumination and the tendency to ruminate has been linked to an increased likelihood to poor mental health. Mindfulness has benefits for not only focus but also for lessening the impact negative thoughts have on us.
Another piece of research that monitored how people felt during the course of the day found that people tended to rate their mood as more positive when they were engaged in an activity that was all-absorbing. i.e. activities where you are less likely to be distracted. This could be cooking, reading, gardening, painting, losing yourself in 'creative flow' or even washing up - activities where people resign themselves fully to just doing that activity. (I find it interesting that often, when we are on 'screens' we flit about from media to media in a highly distracted way - probably why we don't feel great after time spent doing this). Mindfulness is about taking ourselves very much into the moment.
When we learn to be mindful, our minds simply become less frantic, our ability to focus increases, we become less likely to judge ourselves (or others) harshly or let negative emotions have such severe or lasting impact. It's good stuff!
And of course, it's never too early to start. there are many books written on the topic but these websites are a good starting place:
I would add that for adults, meditation seems to fast-track us to the benefits of mindfulness.