I think mediation is a very aiki process.
If you sit and think to yourself " I will not be distracted", then you will get distracted.
If you worry over your mind wandering, then it will wander.
the more you fight it the more it will resist you.
So, relax and think to yourself, I am going to experience sitting.
You sit, and no matter what happens, what thoughts come into your head, you are still sitting. Allow the thoughts to flow, it doesn't matter if they are their or not. the more you make it an issue the harder it is to get rid of them.
sit and experience sitting and everything that comes with it.
in letting go of the limitations you put on your meditative experience (i.e. no thoughts, must relax, must follow the rules you have on meditation), you allow the experience to just occur and those things that you wish to happen fall into place without any effort.
most of all... give it time and enjoy it