In meditation, especially early on in your practice, you will find yourself fidgety. Attention drifts, as it does when we focus on other things as well (work, personal life, wherever). The important thing is not to fight with yourself over the distraction, but to accept it, acknowledge it, and then it let it past you.
Like a rock in a river, many different things may bump and nudge you. You do not push back, but let it roll past you on its own journey.
Mindfully accepting distraction, and releasing it, is as much a part of meditating as the sitting in stillness.
Michael's Musings 